385 cau hoi ve hoa hoc

8/9/2019 385 cau hoi ve hoa hoc

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385 cu hi v p v ha hc vi i sng

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Li ni u

Gio dc th k 21 da trn c s xy dng x hi hc tp vi 4 tr ct l:

- Hc bit (ct li l hiu)

- Hc lm (trn c s hiu)

- Hc cng sng vi nhau (trn c s hiu nhau)

- Hc lm ngi (trn c s hiu bn thn)

Mt khc trc s bng n thng tin v s lo ho nhanh ca kin thc

con ngi mun tn ti v pht trin u phi hc thng xuyn, hc sut

i.

Ho hc l mt khoa hc nghin cu cc cht v s bin i ca chng.

Cc cht to nn mi vt th ca th gii v sinh v hu sinh, chnh chng to

nn c c th chng ta.

Ho hc ch ra nhng cht rn hn kim cng, bn hn st thp, trong

hn pha l, p hn nhung la.

Cun sch 385 cu hi v p v ho hc vi i sng gip cc em

hc sinh m rng kin thc ho hc v nht l tp vn dng kin thc gii

thch cc hin tng thng gp trong i sng, lao ng sn xut, thin

nhin v mi trng. Cui sch gip cho s hiu bit v ho hc ca cc em

su sc,hn v hu ch hn.

i vi cc thy c gio, cun sch cung cp thm t liu cho ccbi dy hc trn lp phong ph, sinh ng hn v hp dn hn.

Tc gi

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1. Phn chua l cht g ?

Phn chua l mui sunfat kp ca nhm v kali. dng tinh th ngm

24 phn t H2O nn c cng thc ho hc l K2SO4.Al2(SO4)3.24H2O.Phn chua cn c gi l phn nhm, ngi ta bit phn nhm cn

trc c kim loi nhm.

Phn nhm c iu ch t cc nguyn liu l t st (c thnh phn

chnh l Al2O3), axit sunfuric v K2SO4.

Phn chua khng c, c v cht chua, t tan trong nc lnh nhng tan

rt nhiu trong nc nng nn rt d tinh ch bng kt tinh li trong nc.

Cng do to ra kt ta Al(OH)3 khi khuy phn vo nc dnh kt

cc ht t nh l lng trong nc c thnh ht t to hn, nng v chm

xung lm trong nc.

Anh ng bc bc lm cao

Phn chua em nh nc no cng trong

Phn chua rt cn cho vic x l nc c cc vng l c nc

trong dng cho tm, git.

V cc phn chua trong v sng cho nn ng y cn gi l minh phn

(minh l trong sng, phn l phn).

Theo y hc c truyn th:

Phn chua, chua cht, lnh lng

Gii c, to thp, st trng ngoi da

D dy, vim rut, thp t

Dng liu tht t, thuc rt hay

Phn chua lm ht nga, st trng v vy sau khi co mt xong, th ct

tc thng ly mt ming phn chua to xoa vo da mt cho khch.

Phn chua dng bo ch ra cc thuc cha au rng, au mt, cm

mu, ho ra mu (cc loi xut huyt).

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2. Hn the l cht g ?

Hn the l cht natri tetraborat (cn gi l borac) ng y gi l bng sahoc nguyt thch, dng tinh th ngm 10 phn t H 2O (Na2B4O7.10H2O).

Tinh th trong sut, tan nhiu trong nc nng, khng tan trong cn 900.

Trc y ngi ta thng dng hn the lm cht ph gia cho vo gi

la, bnh ph, bnh cun cho nhng th ny khi n s cm thy giai v

gin. Ngay t nm 1985 t chc th gii cm dng hn the lm cht ph

gia cho thc phm v n c, c th gy sc, try tim, co git v hn m.

Natri tetraborat to thnh hp cht mu vi nhiu oxit kim loi khi

nng chy, gi l ngc borac.

Trong t nhin, borac c dng khong vt tinkan, cn kenit cha

Na2B4O7.4H2O. Borac dng sn xut men mu cho gm s, thu tinh mu

v thu tinh quang hc, cht lm sch kim loi khi hn, cht st trng v cht

bo qun, cht ty trng vi si. Hn the cn c dng bo ch dc

phm.

Theo ng y, hn the c v ngt mn, tnh mt dng h st, tiu vim,

cha bnh vim hng, vim hnh nhn hch, sng lot rng li.

Hn the ngt, mn, mt thay

Tiu vim, h st, li hay au u

Vim hng, vim li lu

Vim hch, vim mt thuc u snh bng.

Ty y dng dung dch axit boric long lm nc ra mt, dng natri

tetraborat ch thuc cha au rng, li.

3. M chnh (bt ngt) l cht g ?

M chnh l mui natri ca axit glutaric, mt amino axit t nhin, quen

thuc v quan trng. M chnh c tn ho hc l monosodium glutamat, vit

tt l MSG. MSG c trong thc phm v rau qu ti sng dng t do hay

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dng lin kt vi protein hoc lipt. Tuy hm lng thp, song chc nng

ca n l mt gia v, tng v cho thc phm, lm ni bt s ti sng, cn

trong ch bin lm tng s ngon ming. Ngi Hoa (v nhiu dn tc Chu ) li dng chc nng ny trong k xo m thc ch bin cc mn n thm

phn ngon ming trong cc nh hng Trung Quc. Bn thn MSG khng phi

l mt vi cht dinh dng v ch c MSG t do dng ng phn L mi l cht

tng v, cn dng lin kt vi protein v lipit th khng c chc nng ny.

Nhng thc n giu protein nh sa, tht, c cha nhiu MSG dng lin

kt. Ngc li rau, qu, c li tn ti dng t do nh nm c 0,18%, c

chua 0,14%, khoai ty 0,1%.

Ngi Nht lc u phn lp MST t to bin, cn ngy nay MSG

c tng hp bng cng ngh ln men.

M chnh l mt gia v nh hng, i khi h tr cho mt k thut nu n

ti, thng b lm dng v liu lng.

c nhng pht hin v di chng ca bnh n nhiu m chnh m

ngi ta gi l hi chng hiu n Tu: Nh th c cm gic nga ran nh

kin b trn mt, u hoc c c cm gic cng cng mt. Nng th nhc

u, chng mt, bun nn.

Nh vy m chnh c c hi khng? khng t ln MSG c em

ra bn ci cc t chc lng nng th gii (FAO) Y t th gii (WHO). U

ban chuyn gia v ph gia thc phm (JECFA). Ln u tin (1970) c

quy nh rng lng MGS s dng an ton hng ngy l 0 120mg/kg th

trng, khng dng cho tr em di 3 thng tui. Nm 1979 li c quy nh

tng ln l - 150mg/kg th trng. Ti nm 1986 JECFA li xem xt li v xc

nh l MSG khng c vn g.

Tm li, MSG l an ton trong liu lng cho php. iu ng lu l

m chnh khng phi l vi cht dinh dng m ch l cht tng v m thi

4. S a l cht l g ?

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Ngy t thi c xa, ngi ta bit n thu tinh v x phng.

sn xut ra chng ta, phi dng natri cacbonat (sa) khai thc trn b ca

nhng h sa Chu Phi v chu M hoc thu c t tro ca nhng loithc vt mc di bin v b bin chu u. Khong 150 nm v trc, s

a bt u c sn xut bng phng php cng ngh. Mt ngi Php tn

l LBlan tm ra qui trnh u tin sn xut s a. Nhng t nm 1870,

phng php ca ngi B tn l Solvay c li nhun ln hn y li c

phng php ca L Blan v nm 1916; nh my cui cng sn xut theo

phng php ny b ng ca.

Sa c ngha cc k quan trng trong nn kinh t quc dn. N

c dng sn xut cc cht ty ra v cht lm sch trong cng nghip

thu tinh v cng nghip dt. Trong ngnh luyn kim, ngi ta dng n

tch lu hunh ra khi st v thp; sa c dng trong sn xut natri silicat, natri

photphat v natri aluminat, men s, sn du v cng nghip dc phm. Cng

nghip da, cao su, ng; sn xut thc phm, vt liu nhip nh cng cn

n sa. N l thnh phn khng th thiu trong vic lm sch nc !

5. Si ho hc l g ?

Si ho hc l si to thnh t cc cht hu c thin nhin v cc

polime tng hp.

Si ho hc chia lm hai nhm ln: si nhn to v si tng hp. Si

nhn to thu c khi ch bin ho hc cc polime to si, thu c nh tng

hp ho hc. Cc loi si poliamit, polieste, polipropilen v nhiu si khc

na nh capron, nilon, lavsan,v.v l si tng hp.

Si nhn to ra i trc si tng hp. Ngay t nm 1853, Anh

ngi ta xut vic to si mnh di v tn t dung dch nitroxenluloza

trong hn hp ru v ete. Ngi ta sn xut cc loi si ny trn quy m

cng nghip, cch y khng lu lm vo cui th k XIX, u th k XX. T

visco, sn xut t nm 1905, n nay vn cha mt ngha. Si visco thu

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c t dung dch xenluloza m c trong xt long. T nm 1910 n

1920, ngi ta tin hnh sn xut cng nghip t xenluloz axetat.

Lch s si tng hp bt u nm 1932. Lc , c bt u snxut cng nghip si tng hp u tin l polivinylclorua dng vo mc ch

k thut. Khi clo ho tip polivinylclorua ta c nha peclovinyl, t c

th sn xut ra loi si bn v mt ho hc: si clorin. Nm 1930, ngi ta bt

u sn xut si t nha poliamit, l polime tng hp tng t protein. Trong

phn t ca chng, cng ging nh trong protein, c cc nhm amit- CO-NH-

lp li nhiu ln. Cc si poliamit u tin l nilon v capron, v mt s tnh

cht cn tt hn c t thin nhin. Nhng si tng hp c bn cht ho hc

khc nh polieste, poliolefin (trn c s trng hp etylen),v.v cng xut

hin.

V nguyn l, cng ngh sn xut si tng hp l n gin: n khi

nng chy hoc dung dch polime qua nhng l rt nh ca khun ko vo

mt bung cha khng kh lnh, ti y, qu trnh ng rn xy ra, bin dng

polime thnh si. Bng cch , ta thu c si capron v nilon.

Ch t hnh thnh lin tc c cun vo ng si.

Nhng khng phi tt c cc loi si ho hc u c sn xut n

gin nh vy. Qu trnh ng rn si axetat xy ra trong mi trng khng

kh nng, ng rn ch t ca s visco v mt loi si khc li xy ra trong

cc b ng t cha cc ho cht lng c chn lc c bit. Trong qu trnh

to si, trn cc ng si ngi ta cn ko cng cc phn t polime dng

chui trong si c mt trt t sp xp cht ch hn (sp xp song song nhau).

Khi , lc tng tc gia cc phn t tng ln lm bn c hc ca si

cng tng ln. Ni chung, tnh cht ca si chu nh hng ca nhiu yu t

khc nhau nh thay i tc nn p, thnh phn v nng cc cht trong

b ng t, nhit ca dung dch ko si v ca b ng t (hoc bung

khng kh), thay i kch thc l ca khun ko. L cng nh th si cng

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mnh v lc b mt s cng nh hng nhiu n tnh cht ca vi lm t si

ny. tng nhng lc , ngi ta thng dng cc khun ko vi l c tit

din hnh sao.i vi cc chuyn gia dt th di ko t, do si b t di tc

dng ca trng lng chnh n, c xem nh mt c trng quan trng v

bn ca si. Vi si bng thin nhin, di thay i t 5 n 10km, t

axetat t 30 n 35km, si visco ti 50 km, si polieste v poliamit cn di

hn na. Chng hn vi si nilon loi cao cp, di ko t ln ti 80km.

Si ho hc thay th mt cch c kt qu cc loi si thin nhin l

t, len, bng v khng t trng hp vt cc loi si thin nhin v cht

lng.

Sn xut si ho hc c tm quan trng ln lao i vi nn kinh t quc

dn, gp phn nng cao phc li vt cht cho con ngi v c kh nng p

ng nhu cu ngy cng tng ca nhn dn v cc mt hng thng dng: vi,

cc sn phm dt kim v t lng nhn to.

6. Saccarin l cht g ?

L cht tinh th khng mu c v ngt, t tan trong nc. c iu

ch t toluen. Saccarin thng mi l tinh th mui natri ngm nc ca

saccarin, ngt hn ng 500 ln. Dng thay cho ng khi c bnh tiu

ng. C th khng hp th c saccarin.

7. Thn sa l cht g ?

L khong vt thu ngn sunfua HgS, nguyn liu ch yu sn xut

thu ngn.

8. Cholesterol l cht g?

8

CO

NH

SO2

C6H4


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L mt sterol chnh c ph bin trong m ngi, ng vt v mt s

thc vt, di dng t do hay este vi axit bo mch di l cht cn thit cho

c th (thnh phn ca protein, huyt thanh, mng t bo, cht to homon giitnh, axit mt) nhng nu c nhiu cholesterol trong mu s to iu kin

cho cht bo giu axit bo no bm vo thnh trong ca ng mch n mc

c th ngn mu khng lu thng.

9. ADN l cht g ?

L nhng axit nucleic v c phn t khi ln ti hng chc triu vc (hay u).

ADN l thnh phn ch yu ca nhim sc th trong nhn t bo ca

phn ln sinh vt, c vai tr quyt nh nhng c trng di truyn bng cch

iu chnh s tng hp protein trong t bo.

10. Qu t v ht tiu cha cht cay l cht g ?

Chng c nhng loi ancaloit khc nhau. Ancaloit l loi hp cht hu

c c cha nit c tnh baz, thng c ngun gc thc vt, a s c cu trc

phc tp, thng l cc cht d vng.

Ancaloit trong t c tn l capsicain. Cht ny pha long 10 vn ln

vn cn rt cay.

Ancaloit trong ht tiu l hai cht c tn l chavixin v piperin. Cht

chavixin to ra v cay hc ca ht tiu.

11. Cn kh l cht g ?

cc nh hng thng dng loi cn kh t thay cho bp ga khi n

cc mn lu. chnh l cn c cho vo mt cht ht dch th, loi bt ny

hin c sn xut v nhiu mc ch khc nhau: cho vo t lt, cho vo t

chng trng thi hn hn ko di, cho vo cn th d cht norsocryl ca

hng Snow Business c th bin mt lng dung dch c trng lng ln hn

cht ny ti 500 ln thnh cht kh.

12. Cloramin l cht g m st trng c ngun nc ?

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L cht NH2Cl v NHCl2. Khi ho tan cloramin vo nc s gii phng

ra clo. Clo tc dng vi nc to ra HOCl.

Cl2 + H2O HOCl + HClHOCl c phn t rt nh, d hp th trn mng sinh hc ca vi sinh

vt, ph hu protein ca mng, cn tr tnh bn thm ca mng, thay i p

sut thm thu ca t bo v lm cht vi khun, nm.

HOCl c tnh oxi ho rt mnh nn ph hoi hot tnh mt s enzim

trong vi sinh vt, gy cht cho vi sinh vt.

Cloramin khng gy c hi cho ngi dng nc c kh trng

bng cht ny.

13. Bt git gm nhng cht g ?

Bt git l hn hp dng bt, xp bao gm cht ty ra tng hp, cht

hot ng b mt cao (th d natri oexylbenzen sunfunat) s a, cc ph gia

(tripoliphotphat, cacboximetyl xenluloz) cht ty trng, cht thm...

14. Bt ty l cht g ?

L clorua vi Ca(OCl)2.CaCl2.8H2O, hoc biu din thnh phn chnh

l CaOCl2. Cht bt trng, mi clo, phn hu trong nc v trong axit, iu

ch bng cch cho clo tc dng vi vi ti.

2Ca(OH)2+ 2Cl2Ca(OCl)2+ CaCl2+ 2H2O

15. Nc Booco l g ?

L hn hp dung dch ng sunfat v sa vi, dng lm cht dit nm

cho cy trng, nht l cho c chua, nho (cha bnh xon l do nm)

16. Nc cng toan l g ?

L hn hp gm mt th tch dung dch axit nitric c v 3 th tch

dung dch axit clohidric c. C tnh oxi ho mnh, ho tan c vng, bch

kim v hp kim khng tan trong cc dung dch axit v c thng thng.

17. Nc kh l g ?

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L cacbon ioxit CO2 dng rn, khi bay hi thu nhit rt ln, lm h nhit

ca mi trng xung quanh. Dng bo qun thc phm khi chuyn i xa.

18. Du chui l cht g ?Du chui l este ca axit axetic v ru amylic.

Du chui c cng thc l CH3COOC5H11

19. Thch aga - aga l cht g ?

Aga - aga (ch Malaixia ngha l rong) l hn hp cht tch ra t mt

s loi rong bin, thnh phn ch yu l polisaccarit (70%). Dung dch 0,5 -

1,5% trong nc si, khi ngui ng t li thnh thch aga - aga c dng

trong ho hc, vi sinh hc, cng nghip thc phm (lm mt, ko vin)

20. Aming l cht g ?

l khong cht dng si, c thnh phn ho hc l silicat ca magic,

canxi v mt s kim loi khc. Aming bn vi axit, chu nhit, c th ko

thnh si, dt vi may qun o chng chy, dng lm vt liu cch nhit, cch

in, vt liu xy dng nh xi mng aming. Hin nay nhiu nc cm dng

v cht ny c th gy bnh ung th v bnh phi.

21. Apatit l cht g ?

Apatit l khong cht cha photpho c cng thc chung l Ca 5X (PO4)3

(X l F, Cl hay OH) ph bin nht l floapatit. tnh Lo Cai nc ta tr

lng apatit ln ti hng t tn, Apatit l nguyn liu chnh sn xut phn

ln, phot pho (dng trong quc phng, lm dim, thuc tr su), axit

photphoric

22.Cao su l g ?

Cao su l vt liu c tnh n hi (c tnh c th bin dng khi chu lc

bn ngoi tc dng nhng li tr li hnh dng ban u khi lc tc dng khng

cn). Cao su c th b ko dn gp 10 ln chiu di ban u. Tnh n hi ca

cao su l do tnh linh hot ca cc phn t trong mch polime. Tuy nhin

trong thc t, cao su l hn hp cc polime, nn nu lc ngoi tc ng qu

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mnh th cao su mt hon ton tnh n hi. Vo nm 1839, nh ho hc M

Charles Goodyear pht minh ra k thut lu ho cao su c tc dng lm

tng c tnh c l ca cao su, do m rng rt nhiu kh nng ng dng can.

Cao su thin nhin l poli-cis-isopren c ly ch yu t cy cao su

(Hevea barasiliensis) c trng nhiu Nam M. Cy cao su c trng

nc ta t nm 1887 v hin nay c trng tp trung cc tnh min ng

Nam B.

Cao su tng hp (Cao su Buna, cao su Buna-S, ) c pht trin

mnh t chin tranh th gii ln II do s khan him cao su thin nhin. Hu

ht cc cao su tng hp u l sn phm ca cng nghip du m.

23. Teflon l cht g ?

Teflon c tn khoa hc l politetrafloetilen (-CF2-CF2-)n. l loi

polime nhit do, c tnh bn cao vi cc dung mi v ho cht. N bn trong

khong nhit rng t - 1900C n + 3000C, c bn ko cao (245 -

315kg/cm3) v c bit c h s ma st rt nh v bn nhit cao, ti 4000C

mi bt u thng hoa, khng nng chy, phn hu chm. Teflon bn vi mi

trng hn c vng v platin, khng dn in.

Do c cc c tnh qu , teflon c dng ch to nhng chi tit

my d b mi mn m khng phi bi mi (v ma st nh), v cch in,

trng ph ln cho, ni chng dnh.

24. Cht mu azo l cht g ?

T phenyl amin (anilin) v cc arylamin khc, ngi ta tng hp c

mt lot (hng trm nghn) cht mu azo lm phn nhum khc nhau c cng

thc chung l : Ar - N = N-Ar

Tu theo cu trc ca cc gc aryl (phenyl, naphtyl...) ni vi nhm

azo - N = N - m c c cc cht mu azo c mu sc , xanh, tm hay

vng khc nhau... p, bn.

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tng hp cht mu azo, ngi ta cho mt arylamin phn ng vi

HNO2HCl 0 - 50C thnh arylamonihalogenua, ri phn ng tip vi mt

aren hot ng (aren c nhm th loi mt). Ngoi hp cht mu monoazo(c mt nhm azo) cn c th tng hp cc cht mu i azo (c hai nhm

azo), tri azo (c ba nhm azo)...

25. Si thu tinh v si quang l g ?

a- Khi ko thu tinh nng chy qua mt thit b c nhiu l nh, ta

c nhng si c ng knh t 2 n 10 m (1 micromet = 10-6m) gi l

si thu tinh.

Bng phng php li tm hoc thi khng kh nn vo dng thu tinh

nng chy, ta thu c nhng si ngn gi l bng thu tinh. Si thu tinh

khng gin v rt dai, c chu nhit, bn ho hc v cch in cao,

dn in thp.

Nguyn liu sn xut si thu tinh d kim, r tin, vic sn xut

kh n gin, nn hin nay c dng rng ri trong cc lnh vc k thut

khc nhau: sn xut cht do thy tinh: lm vt liu lc; ch to vt liu cch

in: may o bo h lao ng chng chy, chng axit; lt cch nhit cho cc

ct chng ct: lm vt liu lin kt trong ch to my, xy dng; ch to si

quang v.v..

b- Si quang, cn gi l si dn quang, l loi si bng thu tinh thch

anh c ch to c bit, c tinh khit cao, c ng knh t vi

micromet n vi chc micromet. Do c cu to c bit, nn si quang

truyn c xung nh sng m cng b suy gim rt t. Si quang c

dng ti thng tin c m ho di dng tn hiu xung laze. Mt cp

si quang nh nh si tc cng c th truyn c 10000 cuc trao i in

thoi cng mt lc. Hin nay, si quang l c s cho phng tin truyn tin

hin i, pht trin cng ngh thng tin, mng internet iu khin t ng,

my o quang hc v.v

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Cp quang l cc si quang c bc cc lp ng, thp v nha.

26. Thuc chut l cht g?

Ti sao nhng con chut sau khi n thuc chut li i tm nc ung.Vy thuc chut l g ? Ci g lm chut cht ? Nu sau khi n thuc m

khng c nc ung n cht mau hn hay lu hn ?

Thuc chut l Zn3P2 sau khi n Zn3 P2 b thu phn rt mnh, hm

lng nc trong c th chut gim, n kht v i tm nc:

Zn3P2 + 6H2O 3Zn(OH)2+ 2PH3

Chnh PH3 git cht chut.

Cng nhiu nc a vo PH3 thot ra cng nhiu chut cng

nhanh cht. Nu khng c nc chut cht lu hn.

27. 2,4-D, 2,4,5-T v ioxin l nhng cht g ?

Vo khong nhng nm 1940 - 1948 ngi ta pht hin thy rng axit

2,4 - iclophenoxiaxetic (2,4-D) , axit 2,4,5 -triclophenoxiaxetic (2,4,5-T)

nng c phn triu c tc dng kch thch s sinh trng thc vt nhng

nng cao hn chng c tc dng tiu dit cy c. T chng c sn

xut quy m cng nghip dng lm cht dit c pht quang rng rm. Trong

qu trnh sn xut 2,4-D v 2,4,5-T lun to ra mt lng nh tp cht l

ioxin. l mt cht cc c, tc dng ngay nng cc nh (c phn

t) , gy ra nhng tai ho cc k nguy him (ung th, qui thai, d tt).

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OCH2COOH

Cl

Cl

2,4-D

OCH2COOH

Cl

Cl

2,4,5-T

Cl

Cl

Cl

O

OCl

Cl

ioxin


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Trong cuc chin tranh Vit Nam , quc M ri xung Min Nam

nc ta hng vn tn cht c mu da cam trong cha 2,4-D , 2,4,5-T v

ioxin m hu qu ca n vn cn cho n ngy ngay.28. en ailin l cht g ?

Trang phc mu en c nhiu ngi a chung.

Cht mu en nhum vi c nhiu loi, trong c en anilin.

en anilin c iu ch trc tip trong thng nhum vi hoc si, v n

khng tan trong nc. iu ch en anilin, ngi ta cho anilin tc dng

vi cht oxi ho mnh nh KClO3, K2Cr2O7 vi cht xc tc l mui st hay

ng.

Nm 1834, F.F Runge xc nh cu to ca en anilin thuc loi

para - quinonimit:

29. Thy tinh hu c plexiglas l cht g ?

Polimetyl l loi cht do nhit, rt bn,

cng, trong sut. Do c gi l thu tinh hu c hay plexiglas. Plexiglas

khng b v vn khi va chm v bn vi nhit. N cng bn vi nc, axit,

baz, xng, ancol, nhng b ho tan trong benzen, ng ng ca benzen, este

v xeton. Phn t khi ca plexiglas c th ti 5.106. Plexiglas c khi lng

ring nh hn thu tinh silicat, d pha mu v d to dng nhit cao.

Vi nhng tnh cht u vit nh vy plexiglas c dng lm knh my

bay, t, knh trong cc my mc nghin cu, knh xy dng, dng gia

nh, trong y hc dng lm rng gi, xng gi, knh bo him Nhiu c s

vt liu xy dng coi thu tinh hu c l thu tinh kim loi.

15

==N N

CH2 C

CH3OCO

CH3

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Nhiu nc sn xut thu tinh hu c vi nhng tn khc nhau: acripet

(Nht), iakon (Anh), impelex(M) veril ()

30. Tuyt nhn to lm t cht g ?Khi gi lm tuyt ri rp ht hay phim trng, gii k xo u dng tuyt

nhn to bng cht do. Tuy nhin, khi xong vic, h khng th thu gom ht

chng, nht l trn cc bu ca, dn n nhim mi trng. Cc nh ho hc

c to ra mt loi tuyt mi, rt d phn hu, v lm ttinh bt khoai ty.

Sn phm ny l ca Frithjof Baumann v cng s Vin cng ngh

Ho hc Fraunhofer Karlsruhe (c). lm ra n, ngi ta c th dng

tinh bt khoai ty, ng, thm ch to bin. Khi c phun vo trong khng

kh, loi tinh bt ny ho thnh mt dng bt xp, trng ging nh tuyt. Tuy

nhin n lc ny, Baumann vn cha th lm cho tuyt gi ri di dng

bng, m ch c th m phng cch ri ca cc cm tuyt ln. v th nhm

nghin cu vn ang tip tc ci tin n.

Khi c dp m va phi, tuyt khoai ty s dnh kt vi nhau va

p ngi tuyt hay to ra cc ct bng, cn khi phun m nc, chng s

tan ra. Trong khng kh loi tuyt ny ri rt p, nhng n khng hin ra

trn mt t, v qu nh.

Cc nh nghin cu ca vin Fraunhofe th nghim chng trong nh

ht quc gia Karlsruhe, v cung cp 5 tn tuyt cho mt chng trnh khoa

hc gi tng trn ti vi, c tn gi l hnh tinh bng gi.

31. Cht gy nghin l nhng cht g ?

Ma tu d dng no khi a vo c th con ngi c th lm thay i

mt hay nhiu chc nng sinh l.

Ho hc nghin cu lm r thnh phn ho hc ca nhng cht ma

tu t nhin, ma tu nhn to v tc dng sinh l ca chng. T s dng

chng nh l mt loi thuc cha bnh hoc ngn chn tc hi ca cc cht

gy nghin.

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Ma tu gm nhng cht b cm nh thuc phin, cn sa, heroin, cocain,

mt s thuc c dng theo ch dn ca thy thuc nh moocphin, seduxen,

nhng cht hin nay cha b cm s dng nh thuc l, ruMa tu c tc dng c ch, gim au, kch thch mnh m hoc gy o

gic.

Ma tu c phn loi theo ngun gc t nhin hay nhn to hoc theo

mc gy nghin. Sau y xin gii thiu mt s cht gy nghin ph bin.

Ru:Tu thuc nng v cch s dng, ru c th tc dng tt

hoc lm suy yu nghim trng sc kho con ngi. Vi nhiu ngi, ung

mt lng nh ru cng dn n phn ng chm chp, x tr km linh hot,

thn kinh d b kch ng gy ra nhng trng hp ng tic nh tai nn,

hnh ng bo ngcTrong ru thng cha mt cht c hi l etanal

CH3-CHO, gy nn nao kh chu, nu nng cao c th dn n t vong.

Nicotin:( C10H14N2) c nhiu trong cy thuc l. N l cht lng snh

nh du, khng mu, c mi thuc l, tan c trong nc. Khi ht thuc l,

nicotin thm vo mu v theo dng mu i vo phi. Nicotin l mt trong

nhng cht c mnh (t 1 n 2 git nicotin c th git cht mt con ch),

tnh c ca n c th snh vi axt xianhiric HCN. Nicotin ch l mt trong

s cc cht ho hc c hi c trong khi thuc l (trong khi thuc l c

cha ti 1400 hp cht ho hc khc nhau). Dung dch nicotin trong nc

c dng lm thuc tr su cho cy trng. Nhng ngi nghin thuc l

thng mc bnh ung th phi v nhng bnh ung th khc.

Cafein :( C8H10N4O2) c nhiu trong ht c ph, l ch. Cafein l cht

kt tinh khng mu, v ng, tan trong nc v ru. Cafein dng trong y hc

vi lng nh c tc dng gy kch thch thn kinh. Nu dng cafein qu mc

s gy bnh mt ng v gy nghin.

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Moocphin: C trong cy thuc phin, cn gi l cy anh tc. Moocphin

c tc dng lm gim hoc mt cm gic au n. T moocphin li tinh ch c

heroin c tc dng hn moocphin nhiu ln, c v rt d gy nghin. Hassish:l hot cht c trong cy cn sa cn gi l b c tc dng chng

co git, chng nn ma nhng c tc dng kch thch mnh v gy o gic.

Thuc an thn nh l seduxen, meprobamat c tc dng cha

bnh, gy mt ng, du cn au nhng c tc dng gy nghin.

Amphetamin : Cht kch thch h thn kinh d gy nghin, gy

chong, ri lon thn kinh nu dng thng xuyn.Nghin ma tu s dn n ri lon tm, sinh l. Th d nh: ri lon tiu

ho, ri lon chc nng thn kinh, ri lon tun hon, h hp. Tim chch ma

tu gy tru tim mch d dn n t vong.

Do , phng chng ma tu, khng c dng mt s thuc cha

bnh qu liu ch nh ca bc s, khng s dng thuc khi khng bit tnh

nng tc dng v lun ni khng vi ma tu.

32. Nham thch do ni la phun ra l cht g ?

Bn di v tri t l lp dung nham gi l macma, su t 75 km

n khong gn 3000 km. Nhit ca lp dung nham ny rt cao (2000 -

25000C) v p sut rt ln (ti 1,4 triu atmotphe). Khi v tri t vn ng

mnh nhng ni c cu to mng, c vt t gy th lp dung nham ny

phun ra ngoi sau mt ting n ln.

Macma cu to dng bn lng gm silicat ca st, ca magi. Dung

nham thot ra ngoi s ngui dn v rn li to thnh nham thch.

33. Nguyn t t him l g ?

l 14 nguyn t ho hc xp pha di ca bng tun hon. Gi l

t him v cc oxit ca chng rt ging vi cc oxit khc trong t, ng thi

ch c mt s t cc nc c ngun nguyn liu cha cc nguyn t ny. Hp

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cht ca cc nguyn t t him ngy cng c ng dng rng ri trong cc

ngnh cng nghip thu tinh, gm s, in t, vt liu quang hc, vt liu t

Vit Nam, Trung Quc, n , M, Australia c nhiu nguyn liut him, trong khi Anh, Php, Nht li cha tm thy.

34. V sao than cht thnh ng ln c th t bc chy?

Do than tc dng vi O2 trong khng kh to ra CO2, phn ng to

nhit. Nhit to ra c tch gp dn, khi t ti nhit chy ca than th

than s t bc chy.

35. V sao khi t, kh CO chy cn kh CO2 li khng chy?

Do trong CO2, nguyn t C c s oxi ho cao nht l +4 ri. Trong

CO nguyn t C mi c s oxi ho +2, khi tc dng vi O2 n tng ln +4.

2 4

2 22CO O 2CO+ +

+

36. V sao khng th dp tt m chy ca cc kim loi K, Na,

Mg,... bng kh CO2?

Do cc kim loi trn c tnh kh mnh nn vn chy c trong khquyn CO2

Th d: 2Mg + CO22MgO + C

37. V sao khng dng chai thu tinh m phi dng chai bng nha

(cht do) ng dung dch axit flohiric HF?

Do axit HF l axit yu nhng c tnh cht c bit l n mn thu tinh

v n tc dng c vi oxit silic c trong thnh phn ca thu tinh.SiO2 + 4HF SiF4 + 2H2O

Ngi ta thng li dng tnh cht ny khc ch ln thu tinh.

38. V sao mui th d b chy nc?

Mui n c thnh phn chnh l natri clorua, ngoi ra cn c mt t cc

mui khc trong c magi clorua. Magi clorua rt a nc, n hp th

nc trong khng kh v cng rt d tan trong nc.

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Magi clorua c v ng. Nc mt s khe ni c v ng l do c

ho tan magi clorua. Trong nc bin cng c khng t magi clorua. Nc

cn li sau khi mui kt tinh cc rung mui gi l nc t th c n hnmt na l magi clorua. Ngi ra dng nc t sn xut xi mng magi

oxit, vy liu chu la v c kim loi magi.

39. V sao bi vi vo ch ong, kin t s au?

Do trong nc ca ong, kin, nhn (v mt s cy) c axit hu c tn l

axit fomic. Vi l cht baz, nn trung ho axit lm ta au.

2HCOOH + Ca(OH)2 (HCOO)2Ca + 2H2

40. V sao ban m khng nn nhiu cy xanh trong nh?

Do ban m khng c nh sng cy khng quang hp, ch h hp nn

hp th kh O2 v thi ra kh CO2 lm trong phng thiu O2 v qu nhiu CO2.

Ban ngy do c nh sng mt tri, cy quang hp nn hp th CO 2 v

thi ra O2 (nh cht dip lc)

6nCO2 + 5nH2O (C6H10O5)n + 6nO2

41. V sao nm t n xung ao lm c cht?

t n c thnh phn chnh l canxi cacbua CaC2, khi tc dng vi

nc sinh ra kh axetilen v canxi hiroxit.

CaC2 + 2H2O C2H2 + Ca(OH)2

Axetilen c th tc dng vi H2O to ra anehit axetic. Cc cht ny

lm tn thng n hot ng h hp ca c v vy c th lm c cht.42. V sao ngi ta thng dng tro bp bn cy?

Trong tro bp c cha mui K2CO3 cung cp nguyn t kali cho cy.

43. V sao mui NaHCO3 c dng ch thuc au d dy?

NaHCO3 dng ch thuc au d dy (bao t) v n lm gim lng

axit HCl trong d dy nh phn ng:

NaHCO3 + HCl NaCl + CO2 + H2O

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44. V sao trong cng nghip thc phm, mui (NH4)2CO3 c

dng lm bt n?

(NH4)2CO3 c dng lm bt n v khi trn thm vo bt m, lc nng

bnh (NH4)2CO3 phn hu thnh cc cht kh v hi nn lm cho bnh xp v n.

(NH4)2CO3 2NH3+ CO2+ H2O

45. V sao khi cm b kh ngi ta thng cho vo ni cm mt

mu than ci?

Do than ci xp c tnh hp ph nn hp ph mi kht ca cm kh.

lm cho cm mi kh.

46. V sao nc rau mung ang xanh khi vt chanh vo th chuyn

sang mu ?

C mt s hp cht ho hc gi l cht ch th mu, chng lm cho

dung dch thay i mu khi axit thay i.

Trong rau mung (v vi loi rau khc) c cht ch th mu ny. Trong

chanh c cha 7% axit xitric. Vt chanh vo nc rau lm thay i axit, do

lm thay i mu nc rau. Khi cha vt chanh, nc rau mung c muxanh lt l cha cht kim canxi.

47. V sao khng dng nc ch khi ung tn dc?

Trong l ch c cha 20% tanin v 1 1,5% cafein, cc cht ny c

th lin kt vi mt s hot cht ca tn dc, do lm gim hiu qu ca

thuc.

48. V sao vt chanh vo cc sa c c ng s thy c kt ta?Trong sa c thnh phn protein gi l cazein. Khi vt chanh vo sa

s lm tng chua tc lm gim PH ca dung dch sa. Ti PH ng vi

im ng in ca cazein th cht ny s kt ta. Khi lm phomat ngi ta

cng tch cazein ri cho ln men tip. Vic lm u ph cng theo nguyn tc

tng t nh vy.

49. V sao n sn (c m) hay mng c khi b ng c?

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n sn hay mng b ng c khi chng cha nhiu axit xianhiric

(HCN). dng tinh khit axit xianhidric l cht kh mi hnh nhn, c v

ng v rt c. Nhit nng chy l - 13,3

0

C, tan trong nc, ru, ete vl axit rt yu. Trong thin nhin gp dng lin kt trong mt s thc vt

(ht mn, o, c sn, mng ti).

Sn luc hay mng luc hoc xo nu c v ng l cha nhiu axit

xianhiric, c nguy c b ng c. Khi luc sn cn m vung axit

xianhiric bay hi. Sn phi kh, gi thnh bt lm bnh th khi n

khng bao gi b ng c v khi phi kh axit xianhiric s bay hi ht.

Trong cng nghp axit xianhiric c iu ch bng cch oxi ho hn

hp kh metan (CH4) v amoniac (NH3), c xc tc platin. Axit xianhiric l

nguyn liu iu ch tng hp cc cht cao phn t. Axit xianhiric dng t

do dng lm cht xng hi chng cn trng gy bnh.

Mui ca axit xianhiric nh kali xianua (KCN) dng trong tng hp

hu c, trong nhip nh v tch kim loi vng, bc ra khi qung.

50. V sao sau khi n tri cy khng nn nh rng ngay ?

Cc nh khoa hc khuyn co: Ai n tri cy th phi mt gi sau mi

c nh rng. Ti sao vy ? cht chua (tc axit hu c) trong tri cy s kt

hp vi nhng thnh phn trong thuc nh rng theo bn chy s tn cng

cc k rng v gy tn thng cho li. Bi vy ngi ta phi i n khi nc

bt trung ho lng axit trong tri cy nht l to, cam, nho, chanh.

51. V sao cc vt bng bc lu ngy thng b xm en ?

Do bc tc dng vi kh O2 v kh H2S c trong khng kh to ra bc

sunfua c mu en.

4Ag + O2+ 2H2S 2Ag2S + 2H2O

52. V sao dng dng bng bc ng thc n, thc n lu b i ?

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Khi bc gp nc s c mt lng rt nh i vo nc thnh ion. Ion

bc c tc dng dit khun rt mnh. Ch cn5

1t gam bc trong 1 lt nc

cng dit cc vi khun. Khng cho vi khun pht trin nn gi cho thc n

khng b i thiu.

53. V sao dng dao (bng thp) ct l, to th b mt ch ct s b

en ?

Trong l, to v nhiu loi tri cy c cha tanin. Tanin cn gi l axit

tanic, n tc dng vi st to thnh st (III) tanat c mu en. Tanin c v

cht, qu hng c v cht do rt nhiu tanin.

Tanin tinh khit l cht bt mu vng, d tan trong nc.

C khi khng dng dao bng st ct l, to, hng m sau mt lc,

ch ct vn b thm en l do kt qu ca nhiu bin i ho hc. Trong

phn t tanin c cha nhiu gc phenol, cc gc ny rt mn cm vi nh

sng v rt d b oxi ho bi oxi ca khng kh bin thnh cc oxit c mu

en. V vy tanin thng c bo qun trong cc bnh thu tinh sm mu.

Trong cng nghip tanin dng thuc da v ch mc mu en.

54. V sao h con dao t ln ngn la, con dao s c mu xanh ?

l do nhit cao st tc dng vi nc to nn oxit st t Fe3O4

lp lnh mu lam. Lp o mu lam ny l tm mng bo v st, lm cho st

khng b g v khng b n mn. cc nh my ngi ta em cc ch phm bng thp cho vo dung dch

natri nitrat hoc hn hp natri nitrat v natri hidroxit nhit t 140 ->

1500C. Sau mt thi gian nht nh trn b mt s sinh ra mt lp mng mu

lam, sau ly ra v nhanh chng cho vo nc lnh, ri li em x l bng

nc x phng, du nng my pht. Ngi ta gi bin php ny l ti mui.

Cc ch phm qua ti mui s c tui th di hn.

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55. V sao thu tinh thng c mu xanh ?

Do c cha hp cht ca st. Nu cha hp cht st (II) th c mu

xanh cn cha hp cht st (III) th c mu vng nu.Ni chung thu tinh cha 1->2% st th s c mu xanh hoc vng nu.

Thu tinh quang hc khng mu ch cha khng qu 3 phn vn st.

56. V sao thu tinh li c th t thay i mu ?

Vic ch to thu tinh i mu cng tng t nh ch to thu tinh

thng, ch khc l ngi ta thm vo nguyn liu ch to thu tinh mt t

cht cm quang nh bc clorua hay bc bromua v mt t cht tng nhynh ng clorua. Cht nhy cm lm cho thu tinh bin i nhy hn.

S i mu c th gii thch nh sau: Khi b chiu sng, bc clorua tch

thnh bc v clo. Bc s lm cho thu tinh sm mu. Khi khng chiu sng

na, bc v clo li gp nhau, to thnh bc clorua khng mu, lm cho thu

tinh li trong sut.

57.V sao thm mui qu sm th u khng nh ?

Cc b m thng nhc nh: Khi nu u ch cho mui qu sm, iu

ny c th gii thch mt cch khoa hc nh sau: Trong u nnh kh, nc

rt t. Do c th coi n nh mt dung dch c, v lp v l mt mng bn

thm. Khi nu, nc bn ngoi s thm thu vo trong u lm u nnh n to

ra, sau mt thi gian cc t bo trong ht u b ph v lm cho u mm.

Nu khi nu u ta cho mui qu sm th nc bn ngoi c th

khng i vo trong u, thm ch nc trong u s thm thu ra ngoi do

nng mui trong nc mui bn ngoi ln hn nhiu so vi nng mui

trong u nu cho mui qu nhiu.

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Thng thng khi nu cho u xanh, cho u khng nn thm

ng qu sm hoc nu tht b, tht ln khng nn cho mui qu sm v

cng s kh nu nh.58. V sao n ng glucoz li cm thy u li mt lnh ?

Nu bn cho mt tha ng glucoz vo li trong cm gic ngt

ngo cm nhn c cn c cm gic mt lnh. V sao vy ? Glucoz to ra

mt dung dch ng trn li, s phn b cc phn t ng trong qu trnh

ho tan l qu trnh thu nhit, do ta cm thy u li mt lnh.

59. V sao thc n nu kh chy d gy ung th ?Theo cc chuyn gia ca t chc y t th gii, nu thc n qu chy d

gy ung th. Cht asparagin trong thc phm di nhit cao s kt hp vi

ng t nhin trong rau qu, hay cc thc phm giu cht cacbohirat to

thnh cht acylamid, tc nhn chnh gy ra bnh ung th.

n nhiu tht hun khi v cc cht bo qun thc phm cha nitrosamin

c trong rau ngm, tht hun khi lm gia tng ung th ming, thc qun, thanh

qun, d dy. n nhiu cht bo c lin quan n ung th v, i trng, trctrng, nim mc t cung.

Thuc tr su nitrofen l cht gy ung th v d tt bo thai. Ho cht

c hi ethinnylestradiol v bisphenol A c trong ti nilong v hp nha ti

sinh dng ng thc n gy hi cho bo thai.

60. V sao go np li do ?

Tinh bt c 2 loi amiloz v amilopectin nhng khng tch ri nhau,

trong mi ht tinh bt, amilopectin l v bao bc nhn amiloz. Amiloz tanc trong nc, amilopectin hu nh khng tan, trong nc nng

amilopectin trng ln to thnh h. Tnh cht ny quyt nh n tnh do

ca ht c tinh bt. Trong mi ht tinh bt, lng amilopectin chim 80%,

amiloz chim khong 20%, nn cm go t, ng t, bnh m, thng c

do bnh thng. Tinh bt trong go np, ng np cha lng amilopectin rt

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cao, khong 98% lm cho cm np, xi np, ng np lucrt do, do ti

mc dnh.

61. V sao nc mt li mn ?

Nc mt mn l v trong mt lt nc mt c ti 6g mui. Nc mt

sinh ra t tuyn l nm pha trn mi ngoi ca nhn cu. Nc mt thu nhn

c mui t mu (trong mt lt mu c 9 g mui). Nc mt c tc dng bi

trn nhn cu, lm cho nhn cu khng b kh, b xc v v c mui nn cn

c tc dng hn ch bt s pht trin ca vi khun trong mt.

62. V sao pha trn cng ca ngn la li c mu xanh ?

V ch nhit ca ngn la cao nht. Bnh thng khi nhit

vt qu 10000C th ngn la s c mu xanh hoc mu trng, di 1000 0 C

c mu .

63. V sao axit nitric c li lm thng qun o ?

Axit nitric c l mt dung mi ca xenluloz. Nu b mt nhm bng

vo axit nitric c lc nh mt lc, nhm bng s tan ht.

Khi axit nitric c dnh vo qun o n s ha tan xenluloz ngay nn

s xut hin l ch cc l thng.Khi b axit nitric long dy vo qun o, tuy qun o khng b thng

ngay, nhng khi qun o kh, nng axit tng v tr thnh c s lm thng

qun o.

Nu qun o b dy axit nitric cn git ngay bng mt lng ln nc.

64. V sao va trt tng phi sau my ngy mi cng li c ?

Khi bn n mt cng trng xy dng bn s thy nhng ngi th xy

dng ct vng trn va xy. Loi va vi nho do ny ch sau my ngy l tr

nn ht sc rn, nh cc vin gch c th gn cht vi nhau bn vng. iu

ny c gii thch nh sau: Va vi trt tng c cha vi ti [l Ca(OH) 2]

trong khng kh sau vi ngy do hai bin i:

-Va vi l mt cht keo, do khi nc trong va vi bay hi mt

phn Ca(OH)2 s kt tinh trong dung dch qu bo ho. Cc tinh th ca vi

kt tinh trong cht keo s bin thnh mt tinh th rn chc.

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- Do tc dng cacbonat ho, Ca(OH)2 tc dng vi CO2 trong khng kh

vi s c mt ca nc to thnh CaCO3 tinh th.

Hai bin i trn ng thi xy ra khi va vi tip xc vi khng kh

lm cho va trt tng cng li.

65. V sao hng ngn loi hoa c hng trm mu sc khc nhau ? C

phi hng trm mu sc khc nhau ng vi hng trm cht khc nhau

khng ?

Ngi ta phn tch mu sc ca trn 4000 loi hoa v thy rng hng

trm mu sc khc nhau kia ch l s bin i bin i ca 7 mu c bn l

, nu, vng, lc, lam, tm v trng. Trong phn ln sc mu ca hoa l s

bin ho gia cc mu , tm v lam. Phn nh hn l s bin i gia cc

mu vng, nu v .

Nghin cu k hn, ngi ta cn bit rng trong hoa c cha mt loi

cht gi l hoa thanh t, mt hp cht hu c phc tp to thnh bi benzen

v benzopyran mu sc ca n c th thay i thy theo s thay i PH

ca dch t bo ca hoa. Dch t bo c tnh kim hoa c mu lam, c tnh axit

hoa c mu cn khi trung tnh c mu tm.

66. V sao trong mt ngy hoa ph dung c th i mu ti 3 ln ?

Hoa ph dung i mu 3 ln trong ngy. Bui sng mu trng, bui

tra mu pht hng, bui chiu mu hng m hn.

Loi hoa, trc sau ch bin i thay nhau gia cc mu trng, hng,

vng, da cam, . l do tc ng ca cht caroten thay i trong thc vt.S d c tn nh vy v ln u tin n c chit sut t c carot. dng

tinh khit n l nhng tinh th mu rt p.

Caroten l mt loi sc t thng thy trong mi o hoa. Trong sa

ng vt, trong cht bo cng c sc t ny nhng nhiu hn c l trong c

carot (cht mu vng da cam) Caroten l mt hirocacbon no v c cng thc

l C40H56, trong phn t c 11 lin kt i v 2 vng no.

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67. V sao khi tn la bn trng my bay ta thy xut hin khi

mu nu ?

Nit (IV) oxit NO2c dng lm cht oxit ho trong nhin liu phngtn la.

Khi tn la bn trng my bay th v tr tn la trng ch xut hin

m khi mu nu. l do trong tn la cn d nhin liu l NO2. Khi u

n chm n, ng thi nhin liu d cng bc hi. Nu tn la khng bn

trng mc tiu s bay ht v t hu, khi nghe ting n v quan st ta ch

thy khi trng v lc ny trong tn la ht nhin liu.

68. V sao c kh metan thot ra t rung la ?

nh gi lng kh metan hng nm thot ra v i vo kh quyn ang

l mt thch thc vi cc nh khoa hc. Nhng nh gi ny i hi vic

phn tch mt lng khng l cc s liu.

Nhng nghin cu Trung Quc cho thy c mt lng ln khi metan

sinh ra t s thi ra cc vt th hu c t rung la. Ngi ta c chng

khong 1/7 lng kh metan thot vo kh quyn hng nm l t hot ng

cy cy !

Ngi ta tin hnh 1300 th nghim trong ma gieo trng trong nm

1988 v 1989 Giang Chu (Trung Quc) cho thy lng kh metan thot ra

trung bnh l 58mg/(m2.h). Con s ny Chu u v Bc M l 4 - 6mg/

(m2.h)

69. V sao c th bin tro xng thnh qu ?

Cng ty TifGem ti Chicago (M) c sng kin bin tro xng ca

ngi qu c thnh nhng vin ngc v trong tro xng c cha cacbon.

Ngi ta dng l sy siu nng bin tro xng thnh than ch, sau nn

chng li to ra nhng vin kim cng xanh v vng c gi t 2700 la

ti 20.000 la.

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Thnh cng ca cng ty LifeGem s to s thay i trong vn tm

ni an ngh cho ngi qu c.

70. V sao gi teri l nguyn liu ca tng li ?teri l mt ng v ca hidr ( H21 ). Cc ht nhn ca teri khi kt

hp vi nhau s to ra mt nng lng rt ln. Mt kilogam teri khi kt

hp thnh nguyn t Heli s cho nng lng tng ng khi t 40.000 tn

than.

Phn t nc nng do 2 nguyn t teri ho hp vi mt nguyn t

oxi m thnh.

Trong nc bin, trung bnh c 6000 phn nc th c mt phn t nc

nng. Trong mt lt nc bin c gn 0,02 gam teri. Tng tr lng ca teri

trong nc bin c n 25.000 t tn, tng ng vi 5000 t t tn du m.

Ti sao ni teri l nguyn liu ca tng lai cn hin ti li cha s

dng c ? Vn ch l hin nay cha nm c k thut khng ch

phn ng nhit hch tng hp ht nhn ny.

71. Axit clohiric c vai tr nh th no i vi c th ?Axit clohiric c vai tr rt quan trng i vi qu trnh trao i cht

ca c th. Trong dch v d dy ca ngi c axit clohiric vi nng

khong t 0,0001 n 0,001 mol/l (c pH tng ng l 4 v 3) . Ngoi vic

ho tan cc mui kh tan, axit clohiric cn l cht xc tc cho cc phn ng

thu phn cc cht gluxit (cht ng, bt) v cht protein (cht m) thnh

cc cht n gin hn c th c th hp th c.

Lng axit clohiric trong dch v d dy nh hn hoc ln hn mc

bnh thng u mc bnh. Khi trong dch v d dy, axit clohiric c nng

nh hn 0,0001 mol/l (pH > 4,5) ta mc bnh kh tiu, ngc li, nng

ln hn 0,001 mol/l (pH < 3,5) ta mc bnh chua. Mt s thuc cha au d

dy c cha mui natri hirocacbonat NaHCO3(cn gi l thuc mui) c tc

dng trung ho bt axit trong d dy.

NaHCO3 + HCl NaCl + CO2 + H2OTrong cng nghip, mt lng ln axit clohiric dng sn xut cc

mui clorua v tng hp cc cht hu c.

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Hng nm trn ton th gii sn xut hng triu tn axit clohiric

72. Mt s dch lng thng thng c pH nh th no ?

Mu pH

Dch d dy 1-2Nc chanh 2,4Gim 3,0

Nc nho 3,2Nc cam 3,5Nc tiu 4,8-7,5 Nc ngoi khng

kh

5,5

Nc bt 6,4 - 6,9Sa 6,5Mu 7,3-7,45

Nc mt 7,473. pH v s su rng lin quan vi nhau nh th no ?

Rng c bo v bi lp men cng, dy khong 2mm. Lp men ny

l hp cht Ca5(PO4)3OH v c to thnh bng phn ng :

2 3

4 5 4 35Ca 3PO OH Ca (PO ) OH

+

+ + (1)

Qu trnh to lp men ny l s bo v t nhin ca con ngi chng

li bnh su rng.

Sau ba n, vi khun trong ming tn cng cc thc n cn lu li trn

rng to thnh cc axit hu c nh axit axetic, axit lactic. Thc n vi hm

lng ng cao to iu kin tt nht cho vic sn sinh ra cc axit .

Lng axit trong ming tng, pH gim, lm cho phn ng sau xy ra:

OHOHH 2++ .

Khi nng OH- gim, theo nguyn l L Sa-t-li-, cn bng (1)

chuyn dch theo chiu nghch v men rng b mn, to iu kin cho su

rng pht trin.

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Bin php tt nht phng su rng l n thc n t chua, t ng, nh

rng sau khi n. Ngi ta thng trn vo thuc nh rng NaF hay SnF2, v

ion F

-

to iu kin cho phn ng sau xy ra.F)PO(CaFPO3Ca5 345

3

4

2+

+

Hp cht Ca5(PO4)3 F l men rng thay th mt phn Ca5(PO4)3OH.

Trc y, nc ta mt s ngi c thi quen n tru l tt cho vic

to men rng theo phn ng (1), v trong ming tru c vi ti Ca(OH)2, cha

Ca2+ v OH- lm cho cn bng (1) chuyn dch theo chiu thun.

74. Cuc sng cao v qu trnh sn sinh hemoglobin lin quanvi nhau nh th no ?

Qu trnh sinh l b nh hng bi iu kin mi trng. S thay i

t ngt v cao c th gy ra au u, bun nn, mt mi v kh chu. y

l triu chng ca s thiu oxi trong cc m.

Sng cao vi tun hoc vi thng s dn dn vt qua c chng

say cao v thch nghi dn vi nng oxi thp trong khng kh.

S kt hp oxi vi hemoglobin (Hb) trong mu c biu din mt

cch n gin nh sau:

2 2Hb O HbO+

(Hemoglobin) (Oxi hemoglobin)

HbO2 a oxi n cc m. Biu thc ca hng s cn bng l :

[ ][ ][ ]2OHb

HbOK 2=

cao 3 km, p sut ring phn ca oxi vo khong 0,14 atm so vi

0,3 atm ngang mc nc bin. Theo nguyn l L Sa-t-li-, nng oxi

gim s lm cho cn bng trn chuyn dch sang tri gy ra bnh thiu oxi

trong cc m. Hin tng ny buc c th ngi phi sn sinh ra nhiu phn

t hemoglobin hn v cn bng s chuyn dch t tri qua phi, to iu kin

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cho vic hnh thnh oxihemoglobin. Vic sn sinh thm hemoglobin xy ra t

t. t c cng sut ban u phi cn ti vi nm. Cc nghin cu ch

rng, cc c dn sng lu vng cao c mc hemoglobin trong mu cao, ikhi cao hn 50% so vi nhng ngi sng ngang mc nc bin.

75. Thc phm c chia thnh nhng nhm no ?

Con ngi mun tn ti v pht trin cn phi n. Thc phm l nhng

cht mang li cho c th nguyn liu sn sinh nng lng; to ra t chc

t bo; sinh sn ra cc t bo; hay cc cht mi thay th v d tr khi c

th cn.

V cht dinh dng khng c ng u trong thc phm nn ngi ta

chia thc phm ra lm nhiu nhm m bo s cn i. M chia thc

phm thnh 4 nhm l: b - sa, th - rau, rau - qu v bnh m - ng cc. Vit

Nam chia 5 nhm l: gluxit, lipit, protein cht khong v vitamin.

76. C th chng ta cn nhng hp cht hu c thit yu no ?

C th chng ta cng cha hng nghn loi cc phn t hu c v v c

nn cng c sp xp thnh loi thit yu v khng thit yu ch khi

nui dng.

C 24 hp cht hu c thit yu l: 9 amino axit, 2 axit bo v 13 vitamin.

C 15 thnh phn thit yu v c l: canxi, photpho, it, magie, km, ng,

kali, natri, clo, coban, crom, mangan, molipen v selen (c th k c asen,

vanai v thic).

Cc cht trn c th ly t thc phm nh amino axit ly t tht, trng,

sa axit bo khng no ly t u nnh vitamin ly t rau qu nh

vitamin A trong qu gc, vitamin C trong qu chanh, cam, bi

77. C nc, gan cc, mt c trm c cha c t g ?

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C nc rt c v c cha c t tetraodontoxin, gan cc v trng cc

c v cha bufotoxin, mt c trm c v c mt ancol steroit gy c l 5

cyprinol78. Nn n nh th no ?

cung cp y cc cht thit yu cho c th cn phi bit cch n

nh thay i thc phm (thng gi l n i ba) v n va khng qu

thiu hoc qu tha dinh dng.

79. Thc phm nh hng ti tm trng con ngi nh th no ?

Ngy nay ngi ta khng nh thc phm khng ch c nh hng n

sc kho m cn nh hng ti tm trng con ngi.

Thc n giu protein (cht m) lm cho bn vui ti hn ln. Chng

gip c th sn sinh ra dopamin v norpinephrin lm tng nhit lng c th

khin cho bn c tp trung hn v cn c tc dng gim c stress. Nu

nh trong ba n sng v tra bn dng mt lng protein thch hp s gip

cho bn tnh to, minh mn hn.

Thc n giu cht gluxit (cht bt) c tc dng lm cho bn cng

thng, t b stress v thi gian c th phc hi sau mt mi ngn hn. Khi

n thc n c hm lng gluxit cao th ng thi cng tng lng amino axit

tryptophan a n no, chng c bin i thnh serotonin c tc

dng lm du h thn kinh.

Thc n ngt c tc dng lm du c th. Khi c th tip nhn nhng

thc n ngt th lng ng trong mu tng ln, ng thi phn ng ho hc

ca c th cng c tng cng, khin bn cm thy d chu hn. c bit

ko scla c cha cht phenyletylamin v mt s cht khc c tc dng kch

thch h thn kinh, gy cm gic khoan khoi.

Tri cy nh chui c cha nhiu cht dopamin v norpinephrin l

nhng sn phm ca no c tc ng mnh n cm gic. Tri to cung cp

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cho c th cht x, pectin, nguyn t bo gip duy tr bn ca xng, gi

c phong tnh to, linh hot.

Nc khong c nh hng rt nhiu n tm trng con ngi. Cth chng ta rt cn nhiu nguyn t vi lng. Chng hn, thiu magie c th

d b lm vo tnh trng trm ut, b ph, thm ch cn c th dn n hn

m. Ngoi nc khong, thc n giu nguyn t magie l cm, go tm, ng

cc.

ung c cha cht cafein c tc dng lm cho c th hot bt,

nhanh nhn hn. Song khng nn dng lng cao v c th gy nn nao, cu

knh v au u. Ung sa gip bn ng ngon v tnh to hn khi thc dy.

80. Vitamin l bn hay l th ?

Nm 1970, nh ho hc hai ln c gii Nobel l Lainux Pauling (ln

th nht vo nm 1901) gii thch vitamin C l mt ch phm v hi, tt

nht, c tc dng thn k, c kh nng cha khi bnh cm lnh. Hng ngy

ch cn ung liu t 1 n 4 gam vitamin C, nu cm nng hn th ung liu

cao hn. Vitamin C cha axit ascocbic. Axit ny to thnh cc tinh th khng

mu, d ho tan trong nc, c tng hp trong cc dng cy xanh c dip

lc sng trn cn hay di nc. Con ngi mt kh nng tng hp axit

ny t ng do mt kh nng ch to mt loi men trong qu trnh tiu ho.

Gn y cc nh nghin cu chng minh l dng vitamin C liu cao

c kh nng gim mnh sc khng ca c th chng bnh cm lnh. H

xc nh l c th c th chng li tnh trng tha vitamin C, tuy nhin qu

trnh thi loi vitamin C vn tip tc cho n khi trong c th bt u thiu

ht trm trng vitamin C. C th cng nhn c vitamin C, th vitamin C li

cng b thi loi nhiu. Canada, nm 1965 ghi nhn trng hp cc tr

s sinh mc bnh thiu vitamin C, thng gi l bnh Scocbut. Ngi ta

thy rng cc b m chng ung vitamin liu cao v ngh l s bo v c

sc kho thai nhi. Nhu cu hng ngy v vitamin C ca ngi kho mnh dao

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ng t 0,05 n 0,1 gam. Trong trng hp b cm lnh, c th ch nn tng

liu n 1 gam thi.

81. n th no bo v tim mch ?Theo cc bc s t th k XX trc y cho n th k XXI ny, bnh

tim mch vn l nguyn nhn t vong s 1 ca loi ngi. Theo T chc Y t

Th gii, c 4 giy trn mt t li c mt nhi mu c tim, v c 5 giy mt

tai bin mch no ! cc nc ang pht trin nh Vit Nam, s ngi cht

do bnh tim mch ang tng nhanh chng.

Nhng bnh cht ngi ny, d l bnh tim nh nhi mu c tim hay

bnh mch nh tai bin mch no, u c chung mt nguyn nhn l va x

ng mch. Phi ngn chn c va x ng mch, mi c th gim bt

c t vong v bnh tt ! n ung hp l chnh l mt bin php quan trng

ngn chn va x ng mch, tc l phng nhi mu c tim v tai bin

mch no. Cho nn khng ring g nhng bnh nhn tim mch nn theo, m

c nhng ngi kho mnh bnh thng cng cn ch .

Cc nghin cu gn y nm 2000 a ra nhiu li khuyn v n ung

nh sau:

1.Hn ch cc thc n c nhiu acid bo bo ho, v chng l cc

nguyn liu c th tng hp ra cholesterol xu(LDL-C). C th l nn bt

n cc m ng vt, c bit l m b, m cu (90% cht bo l acid bo bo

ho); ri n b sa. M ln, m g, m chim t acid bo bo ho hn nn

cng khng cn king k lm. c bit m c tuy l m ng vt, nhng li

c t acid bo bo ho, v nhiu acid bo khng bo ho, nn n nhiu bo

v tim mch. Nn ch rng cc du thc vt ni chung cha t acid bo bo

ho, nhng c 2 ngoi l: du da v du c (palm oil) cha acid bo bo ho

nhiu khng km cc m ng vt 45%! Cc nh chuyn khoa tim mch

khuyn co rng t l acid bo bo ho khng nn qu 10% tng s calo;

ngi tng cholesterol th khng nn qu 7%.

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2. Hn ch nhng thc n c nhiu cholesterol nh b (c nhiu trong

sa), trng, c, bu dc, tim, gan, tm, cua Khng nn n qu 300 mg

cholesterol mi ngy, ngi tng cholesterol th khng nn qu 200mg.Trc y, n t cholesterol l li khuyn s 1 gim bnh tim mch.

Tuy nhin cc tc gi gn y khng bt king cholesterol nghim ngt nh

ngy xa v cho rng mt ch n h cholesterol khng nht thit l mt

ch t cholesterol. H thy rng n cholesterol khng hi bng n cc acid

bo bo ho. Th d mt lng trng 17 gam cha 220mg cholesterol, trc

kia ngi ta ch cho n mi tun khng n 2 qu, th nay cc nh tim mch

hc cho php n mi tun 6 qu;

82. i vi c th mui iot c vai tr nh th no ?

c th kho mnh, con ngi cn c cung cp y cc nguyn

t ho hc cn thit. C nhng nguyn t cn c cung cp vi khi lng

ln v c nhng nguyn t cn c cung cp vi khi lng nh (vi lng).

Iot l mt nguyn t vi lng ht sc cn thit i vi con ngi. Theo cc

nh khoa hc, mi ngy c th con ngi cn c cung cp t 1.10-4 n

2.10-4 gam nguyn t iot.

C th tip nhn c phn iot cn thit di dng hp cht ca iot c

sn trong mui n v mt s loi thc phm. Nhng vic thiu ht iot vn

thng xy ra. Hin nay, tnh trn ton Th Gii mt phn ba s dn b thiu

iot trong c th. Vit Nam , theo iu tra mi nht, 94% s dn thiu ht iot

nhng mc khc nhau.

Thiu ht iot trong c th dn n hu qu rt tai hi. Thiu iot lm no

b h hi nn ngi ta tr nn n n, chm chp, c th ic, cm, lit chi,

ln. Thiu iot cn gy ra bnh bu c v hng lot ri lon khc, c bit

nguy him i vi b m v tr em.

khc phc s thiu iot, ngi ta phi cho thm hp cht ca iot vo

thc phm nh : mui n, sa, ko

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Vic dng mui n lm phng tin chuyn ti iot vo c th ngi

c nhiu nc p dng.

Mui iot l mui n c trn thm mt lng nh hp cht ca iot(thng l KI hoc KIO3 ). Th d: Trn 25 kg KI vo mt tn mui n.

Ngi ta cng cho thm hp cht iot vo bt canh, nc mm

Vic dng mui iot tht d dng v n gin. V mi v, mu sc, mui

iot khng khc g mui n thng. Tuy nhin hp cht iot c th b phn hu

nhit cao. V vy phi thm mui iot sau khi thc phm c nu

chn.

83. Cc hp cht v c cha kim loi c tc dng cha bnh nh

th no ?

Cc loi dc phm tuy hu ht l cc hp cht hu c nhng ngi ta

cng nghin cu nhiu hp cht v c dng vo vic cha bnh.

Bng cc phng php nghin cu c trng vt l ca cc nguyn t

kim loi nh tnh phng x, tnh thun tngi ta c th phn tch c ch

tc dng ca cc loi thuc, c bit l vai tr ca cc nguyn t kim loi.

iu ny khng nhng cho php hiu c tnh nng, tc dng ca chng m

cn cho php tm ti c nh hng cc loi thuc mi.

84. C phi hp cht cha platin cha ung th ?

T nhng nm 1965 ngi ta nhn thy hot tnh c ch s pht

trin ca cc vi khun ca cht cisplatin v th dng cht ny cha bnh

ung th ngi.

Ngy nay cc ch phm cha platin thuc nhng thuc hiu qu nht

v c s dng cha ung th cp. Cch thuc cha platin c dng

cha ung th nh: ung th bung trng, ung th rut, ung th phi

Tuy cisplatin l mt tc nhn chng ung th tt nhng qu c. V vy

ngi ta tm cch bo ch ra nhng thuc mi vn gi c hot tnh

nhng t c hn.

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Vic th hot tnh chng ung th ca hng lot cht khc nhau v

nhng nghin cu ng hc v s th phi t cho thy rng khi thay i phi

t hot tnh chng ung th vn c duy tr, cn c tnh th lin quan trctip ti linh ng ca phi t b th. Pht hin ny a n vic iu ch

hng lot dn xut malonat vi linh ng thp hn so vi cisplatin, trong

cacboplatin c chn nh gi lm sng. Kt qu th nghim hon

ton xc nhn cc d on. T 1984 cacboplatin c php s dng Anh

v nhiu nc khc.

Khong 10 ch phm platin khc c th nghim lm sng cc

nc khc nhau. Tr tetraplatin cc cht cn li u l phc cht ca Pt (II)

vi cc nhm b th c linh ng thp hn cisplatin.

85. C phi hp cht cha vng cha vim khp ?

Cc hp cht ca vng c dng cha bnh t nhng nm 1920

nhng ngi ta vn cha r c ch tc dng ca chng.

C nhiu bng chng v hiu qu cha bnh ca cc hp cht cha

vng nhng ngi ta vn lo ngi v c tnh ca chng. C ngi cn ngh

chm dt vic s dng cc hp cht ca vng cha bnh vim khp.

Gii thch c ch tc dng ca vng, mt s tc gi cho rng vng bao

vy cc nhm thiol hot ng. Mt s khc ch ra rng vng c ch vic sinh

sn cc dng oxi hot ng nh ion peroxit cc gc hyroxyl v peroxyl

mng v dch t bo.

Gn y cc nh ho hc v c iu ch c hp cht Auranofin

cha cc phi t to phc bn v c tnh i m, c th dng lm thuc ung,

c tc dng tng t nh cc thuc tim.

86. C phi hp cht cha gali cha mu tng canxi ?

M ngi ta cho php dng galinitrat Ga (NO3)3 cha bnh

mu tng canxi c tnh. Vic ny xut pht t kinh nghim thu c khi dng

mt ng v ca gali trong chun on bnh xng. Ngi ta nhn thy rng

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ngoi cc u xng, gali cng tp trung c mt s u khc, nht l trong bch

huyt.

Nhng nghin cu nhm xc nh sm cc khi u cng vi vic quantm dng cc hp cht ca kim loi lm tc nhn chng ung th thc y

nh th hot tnh chng ung th ca Ga(OH)3 khng phng x trn chut. T

kt qu nghin cu trn chut, ngi ta bt u nghin cu trn ngi. Kt

qu th nghim trn bnh nhn b bnh mu tng canxi cho thy thuc c hiu

qu trong vic a mc canxi trong mu tr li bnh thng v khng c phn

ng ph. S rt canxi t xng c c ch trc tip.

87. C phi hp cht cha bitmut cha vim lot ng tiu ho ?

Cc hp cht ca bitmut c dng cha cc ri lon ng

tiu ho (d dy, rut), t khong 2 th k nay.

Gn y mi quan tm li tng ln khi vo nm 1982 ngi ta pht hin

ra vi khun H.pylori trong mng d dy ca bnh nhn vim d dy.

Mt loi thuc da trn bitmut l antacid t ra c hiu qu trong vic

cha lot d dy, c l do tc dng dit khun chn lc ca n. V mt ho

hc hiu qu gia chng lot c th l do dung dch keo ca bitmut xitrat b

kt ta trong mi trng axit ca d dy di dng oxiclorua v oxixitrat. Do

s kt ta nn lp mng bo v c hnh thnh s ngn cn s khuych tn

ngc li ca ion H+ v do kch thch s ti to biu m.

Hin nay thuc ny c s dng rt rng ri trong cha bnh vim

lot ng tiu ho v so vi cc loi thuc khc th bnh t b ti pht hn.

c th l do s trit tn gc vi khun H.pylori ca thuc.

88. C phi hp cht cha kim loi dng chun on v cha bnh

bng tia phng x.

Trong y hc ht nhn ngi ta chun on bnh bng cch a mt ht

nhn bc x vo c th, sau dng mt my d ghi nhn s phn b

ca ng v phng x xc nh v tr mang bnh v trng thi ca n. Ht

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nhn phng x hay c s dng nht l tecnixi. Tnh u vit ca n l ch

n pht ra photon thun nht thun li cho vic ghi nhn m khng b

nhiu bi cc tia v c hi. Chu k bn hu ca n l 6 gi va ghi nhn m bnh nhn khng phi chu bc x qu lu. Mt khc tecnexi

c sn xut kh d dng trong cc l phn ng ht nhn nn tng i r v

d kim. Nhiu ch phm y hc phng x ca tecnexi c iu ch t sau

nm 1980 c xc nh cu to kh t m v dng chun on bnh tim

hay xc nh bnh no v.v.. Mt trong nhng thnh cng gn y l iu ch

c progestin cha tecnexi nh du chun on ung th v.Cc ion kim loi c gi tr ln trong y hc nh tnh thun t. Cng

hng thun t l phng php chun on quan trng da trn s khc nhau

v tc hi chuyn proton ca nc trong cc m khc nhau v chuyn cc

s khc nhau ny thnh nhng thng tin cn thit gip chun on bnh.

89. Ho hc vi bo qun rau qu nh th no ?

Bo qun rau qu sau khi thu hoch l mt vic rt quan trng nhm

chng h hng v gim st cht lng.

- Dng cc ho cht chng ny mm v dit vi sinh vt gy h hng

rau qu. Chng hn nh chng ny mm cho khoai ty, hnh, c rt v mt

s rau, c khc, ngi ta thng dng ch phm MH- HO (hidrazit ca axit

malic), phun dung dch 0,25% ln cy ngoi ng, 3-4 tun l trc khi thu

hoch. Ngi ta cn chng ny mm khoai ty bng ancol nonilic (C9H19OH)

dng hi.

- bo qun bp ci ngi ta phun cht dit nm pentaclonitrobenzen

ln bp ci trc khi xp vo kho.

- bo qun chui ti, cam ti ngi ta phun thuc dit nm topsin - M.

Trong nhng nm gn y, cht dit nm c dng nhiu l benlate

(C14H18H4O3).

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Cng ho Lin Bang c sn xut ch phm bo qun qu ti c

tn thng mi l protexan. Protexan l cht lng khng mi, khng v v

khng c nn khng nh hng ti sc kho ca ngi tiu dng. Ngi tanhng qu vo dung dch protexan ri hong kh, dung dch bc hi v to

thnh mng mng bo v ngoi v qu. Mng protexan c tc dng gim

tn tht khi lng qu trong qu trnh bo qun, gim cng h hp, lm

chm qu trnh chn nn c th bo qun qu lu di hn, gi nguyn hng

v t nhin v thnh phn dinh dng ca qu.

90. Ho hc vi ch bin rau qu nh th no ?

- Cc qui trnh cng ngh ch bin rau qu thnh cc dng sn phm

khc nhau nh hp, sy kh, ru vang qu.. u cn n mt s ho cht.

+ tng hiu qu cho qu trnh ra sch nguyn liu v my mc,

thit b ca nh my hoa qu ngi ta dng cc ho cht c tnh st trng

mnh hoc c tc dng ty ra cao. Ra nguyn liu th dng cc ho cht c

cha clo hot ng nh clorua vi. ra my mc, thit b v lm v sinh

nh xng ngi ta dng dung dch xt hoc natricacbonat.

+ bc v cc loi qu kh bc v nh mm, c chua, mng mi

cam, qut hoc mt s qu, c c v mng nh c rt, khoa ty ngi ta

dng dung dch NaOH. Nhng cc loi qu, c ny vo dung dch NaOH

nng 1-2% 70 - 800C trong thi gian t 10-300 giy (tu loi qu, c) th

v s trc ht. Sau sa li bng nc sch nhiu ln. Bng cch ny, cc

mi cam, qut v qu s sch ht v m vn gi nguyn hnh trng ban u.

+ ngn nga s bin i mu rau, qu khi ch bin nh chui b

thm en, c chua mt mu ti, ci vi thiu mt mu trng p ngi

ta dng cc cht chng oxi ho nh SO2, axit ascobic (Vi tamin C) axit xitic.

+ tng hng v cho nc qu, qu ng hp ngi ta dng axit

xitric (axit chanh) hoc axit malic (axit to). Vi ru qu ngi ta dng axit

xitrtic, axit tactric (axit nho).

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Vi da chut, c chua, gi xanh th khng th thiu axit axetic.

Rau dm gim (gim l dung dch axit axetic 5%, v chua) cng vi ng,

mui n v gia v to cho sn phm c hng v chua - ngt rt c trng vhp dn. Axit axetic cn c tc dng c ch hot ng ca vi sinh vt, gi cho

sn phm bo qun c di ngy.

Trong ch bin rau qu, rt cn ch bin cc dng bn ch phm d

tr nguyn liu khi ma thu hi r.

bo qun bn ch phm rau qu ngi ta dng cc ho cht c th

to ra SO2 hoc dng axit benzoic, axit sobic v mui ca chng.

Khi dng SO2 bo qun bn ch phm, ngi ta ni bn ch phm

c sunfit ho. Hm lng SO2 c tc dng bo qun l 0,1 - 0,2%. Axit

benzoic hoc natri benzoat c tc dng dit vi sinh vt mnh i vi cc loi

c chua. Hm lng c tc dng dit vi sinh vt l 0,05 - 0,1%. Dng vi

hm lng cao hn s lm cho sn phm c v nng, cht do ho cht gy ra.

Axit sobic l cht bo qun cc bn ch phm rau qu c nhiu u im

hn so vi SO2 hoc axit benzoic v n khng gy c cho ngi s dng v

khng to ra hng v l cho sn phm. Sn phm cng chua ( PH cng

nh) th tc dng dit vi sinh vt ca axit sobic cng mnh.

91. Thnh phn cc mui trong nc bin nh th no?

Thnh phn mui Trong 1 kg nc T l %NaCl 27,2 77,8MgCl2 3,8 10,9MgSO4 1,7 47,0CaSO4 1,2 3,6K2SO4 0,9 2,5CaCO3 0,1 0,3MgBr2 v cc thnh phn khc 0,1 0,2

Tng s 35,0 100

Mui trong nc bin:

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70% b mt tri t l bin. T l gia mui v nc trong nc bin l

khong 3/100 tc l c 3% mui trong nc bin.

92. u c cung in bng mui?Su hn 100 m di lng t trong ni, m mui Ba Lan c mt cung

in lm bng mui. Cng trnh ny c to dng t th k 17. Cc chnh

th iu khc, gi n chm treo trn v c n cc gian phng u c lm

bng mui.

93. Lm th no c con bm bng mui kt tinh?

Un dy thp thnh hnh con bm v qun bng si quanh dy thp

ri t vo nc mui m c. Nc mui t t bay hi v u cc si bng

xut hin cc tinh th mui. i cho tinh th mui xut hin khp cc si

bng, ta li chuyn sang nc mui m c khc. Sau khong 10 ngy ta c

con bm bng mui kt tinh, trng rt p.

94. Dng mui lm kem que nh th no?

Nhit ca nc l 0

0

C. Nu cho mui n vo nhit s gimxung di 00C. Li dng tnh cht ny lm kem que nh sau: Cm que tre

vo ng nc tri cy ri t c vo khay c ng nc ho tan

nhiu mui n. Tt c cho vo lm lnh. Nc tri cy s nhanh chng ng

li thnh kem que.

95. V sao nc bin c mui?

Bin c l "qu hng" ca mui. Mui n (NaCl) chim 85% cc loimui ho tan trong nc bin. Gi s nu chng ta tch c tt c mui khi

nc bin ri ri u trn lc a th lp mui s cao ti 153 m. Cn lm bay

hi ton b nc bin th y bin s c lp mui dy ti 60 m.

tm hiu ngun gc ca mui trong nc bin cc nh khoa hc

tn nhiu cng sc t vic phn tch, so snh nc bin v nc sng, cho

n nghin cu t sau cn ma, thm ch cn nghin cu hng lot ni

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la na. Cui cng h pht hin ra b mt ca mui bin. Ho ra, i

dng trong qu trnh lu di hnh thnh lc ban u ho tan tt c cc loi

mui khong. ng thi nham thch thng qua qu trnh phong ho (nhamthch b tc ng lu ngy ca ma, nng, gi bo v vi sinh vt) khng

ngng b phn gii v sn sinh ra cc loi mui, sau theo cc dng sng

ra i dng. Vy sng ngi, nham thch v cc ni la di y bin chnh

l ngun gc cung cp ch yu cc loi mui cho bin c.

96. Bin Cht nm u?

"Bin Cht" nm bin gii Palestin v Jordan, gi l "bin" nhngthc ra "Bin Cht" ch l ci h kh ln.

Mt bc ca "Bin Cht" c sng Jordan chy vo, cn mt Nam l ca

sng Hasa. Bin cht khng h c ng nc thng vi bt k i dng

no. T bao i nay nc h cha bao gi chy ngc v hai con sng trn.

Nc trong h c nng mui ngy cng cao, do nm trong khu vc c kh

hu cc nng, nn nc h bc hi rt nhiu m lng mui li khng hgim i. Hin nay hm lng mui ca Bin Cht t n 23 25%, tc

c 10 kg nc h th c 2 kg mui. y cng l nc h c hm lng mui

cao nht th gii. Do hm lng mui cao nn sc y ca nc kh ln n

mc c th nm va phi nng va c bo trn mt bin. V hm lng

mui qu cao nn tr vi loi rong to ra chng c sinh vt no c th tn ti

c. Cy c trn b h cng ch l th, tha tht cn quanh h him khi

chng c bng ngi. V vy chng c ci tn no thch hp hn ci tn "Bin

Cht".

97. Cht lng nc cc ngun khc nhau nh th no?

Nc bay hi tch t trong kh quyn l kh sch. Khi tr v tri t

di dng ma hoc tuyt ri di chuyn trn mt t hoc ngm qua t v

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pha bin, nc s c thm tp cht m nng v bn cht khc nhau tu

vng, v tu giai on ca chu trnh.

Nc ma.

Tuy kh tinh khit nhng nc ma vn cha cc kh, mt s mui tan

v c nhng cht rn khng tan c th c trong kh quyn.

Nc trn mt t (sng sui)

Nc ma chy trn mt t c th cha axt v ngoi vic hp th

mt s kh c tnh axt trong kh quyn (nh SO2, CO2) n cn ho tan cc

axt cacboxylic v cacbon ioxit sinh ra do qu trnh phn hu thc vt. Ngoi

ra n cn ho tan c cc mui khong gp trn dng chy. Nc axt ny

s ho tan c cc mui v khong gp trn dng chy. Nc axit ny s

ho tan c mt s qung theo phn ng sau:

KAlSi3O8(r) + 2H+(aq) + 9H2O(1) 2K+(aq) + 4H4SiO4(aq) + Al2Si2O5(OH)4(r)

(fenspat) (Cao lanh)

Do vy nc mt dn tnh axit.

Nc trn mt t cn c th b nhim bi vi sinh vt na.

Nc bin:

Nng cc ion tan trong nc bin ln hn nhiu so vi nc trn

mt t v nc ngm:

Cc nguyn nhn l:

- Nc bin bay hi lin tc, tr li di dng ma v mang theo cht

tan

- Nc i cng xa mi n bin s cng ho tan nhiu mui.

- Nhng lng ln qung c a t b mt qu t ti cc i dng

di dng macma.

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Mi nguyn t ho hc u c trong cc i dng nn i dng c

coi nh mt kho qung ln nht th gii. Nc i dng cha khong 40

triu tn cht rn tan trong mi kilmet khi nc.

Nguyn t S tn/km3 Nguyn t S tn/km3 Nguyn t S tn/km3

Clo 22.000.000 Ini 23 Bc 0,2Natri 12.000.000 Km 12 Lantan 0,2Magie 1.600.000 St 12 Kripton 0,2Lu hunh 1.000.000 Nhm 12 Neon 0,1

Canxi 450.000 Molipen 12 Caimi 0,1Kali 44.000 Selen 4 Vonfram 0,1Brom 75.000 Thic 3 Xenon 0,1Cacbon 32.000 ng 3 Gemani 0,1Stronti 9.000 Asen 3 Crom 0,05Bo 5.600 Urani 3 Thori 0,05Silic 3.400 Niken 2 Scani 0,05Flo 1.500 Vanai 2 Ch 0,02Agon 680 Mangan 2 Thu ngn 0,02

Nit 590 Titan 1 Gali 0,02Liti 200 Antimoan 0,5 Bitmut 0,02Rubii 140 Coban 0,5 Niobi 0,01Photpho 80 Xesi 0,5 Tali 0,01Iot 68 Xeri 0,5 Heli 0,01Bari 35 Ytri 0,2 Vng 0,005

98. Lm ma nhn to nh th no?

Nc tn ti trong my di dng hi, dng lng v dng tinh th.Thng thng 00C nc ng bng, nhng trong nhng m my, d

-200C, cc ht nc nh li ti vn th lng. Ch khi nhit h xung - 40 0C,

nc trong m my mi kt tinh hon ton. S lng tinh th nc trong

my ph thuc vo cc "ht nhn kt tinh" l cc ht bng cha trong , cn

gi l "mm kt tinh".

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Cc nh khoa hc t lu pht hin tinh th bc iotua (AgI) c cu to

rt ging cu to ca cc ht bng nn c th dng lm "mm kt tinh". Ch

vi 1g AgI to ra c t 1012

1016

trung tm kt tinh, lm ngng t mtlng nc ln dng kh to ra ma hoc tuyt.

Bc Iotua l mt ho cht rt t, v vy cc nh ho hc nghin cu

tm cc cht thay th r tin hn l ch Iotua (PbI 2); 1,5 - ioxinaftalen;

nc kh (CO2 rn) v nhiu cht hu c khc.

Dng cc cht trn lm ma vi iu kin l trn tri c sn nhng

m my. Ngi ta dng my bay rc cc cht trn vo my.

Nh phng php ny ngi ta cu mt v gieo trng b hn khi sp

thu hoch, tng m khi ma mng b lm nguy hoc bt mt cn ma sm

c bu tri quang ng trc ngy hi ln.

C nhng k olympic ma ng, ngi ta dng phng php ny

lm tng lng tuyt ln t 10 15%. Nu tnh c hng gi v xc nh

ng a im rc ho cht, c th lm ma nhng im chy rng, khi

ngn la mi bng ln. B lm nghip nc CHLB Nga nhiu ln cu

hng nghn hecta rng Xiberi khi thn la.

99. Lm th no ngn nga ma ?

Rc vo m my nhng "ht nhn kt tinh" khng nhng "thay tri

lm ma" m cn ngn nga c ma , nhng ht bng ang ln dn

chun b cho ma , khng ln ln c na do nhng "mm kt tinh" bng

ho cht tranh cp m. Cc ht bng nh li ti nhiu hn, nhng khng t

n kch thc ca ht ma . Trn ng ri xung mt t chng b tan ra

v tr thnh cn ma bnh thng.

Hin nay c nhng ra a kh tng d bo s hnh thnh nhng m

my cha nhng ht bng. Cc tn la v n cha ho cht c iu khin

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bn trng ch. Nh vy m nhiu vng rng ln cc nc tin tin

trnh c s tn ph ca ma i vi ma mng.

100. Lm th no ph tan sng m?Sng m, th phm gy ra nhng v tai nn ng thu, ng b v

ng khng.

Ngi ta rc hoc bn vo khi sng m cc loi ht nng c tnh ht

m nh mui n (NaCl) trn vi xi mng mn, cc cht hot ng b mt, cc

cht tch in...

Nhng ht nc l lng, dy c trong sng m khi gp "mm kt

tinh" s ng t khin mt ca chng trong khng kh gim dn v cui

cng ri xung di dng nhng ht nc.

Bn cnh phng php ho hc, ngi ta cn dng cc phng php

khc. M, ngi ta ph sng m bng my bay trc thng. Cnh qut ca

my bay ht dng khng kh kh cc lp tng cao xung xua tan sng m.

Sn bay Orly ca Php ph sng m bng lung khng kh nng do mt h

thng tua bin y ra, hng vo ng bng.

101. Lm tan ging bo nh th no?

lm tan ging bo ngi Nga dng my bay rc vo m my

nhng ht bt nng (ct, xi mng) khin m my nhanh chng b tan ra.

Ngi M rc ln m my nhng si ch nilon m kim loi. S phng in

kiu h quang trong in trng gy ion ho khng kh, tng dn in v

lm du i s phng in ca cc in tch v nh vy c th trit tiu sm

chp.

Cc nh kh tng hc rc cc cht kit tinh vo nhng m my ging,

phn b li nng lng v lm gim sc ph hoi ca cc trn bo. Chng hn

M vi trn bo Dally nm 1979, bng cch "x l" ny ngi ta lm tc

gi gim i 1/3.

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Cc nh ho hc cng dng nhng cht hot ng b mt can thip

vo thi tit do lm thay i tnh cht ca b mt nc v t. Dng mt

lng nh ru bo a chc to lp mng cc mng trn mt bin lm gimmnh lng nc bay hi v ngn chn c s hnh thnh nhng m sng

m nguy him bao ph cng, nht l vo ma lnh.

Rc nhng ht m hng trn mt t, iu chnh c t l hp th tia

bc x, lm thay i ch nhit ti mt vng rng ln.

Nhn chung cc phng php ho hc tc ng vo thi tit cn rt t,

khng kinh t v th cha c s dng rng ri.

Con ng ch ng thi tit cn rng m, ang ch i cc nh ho

hc tr tm ra cc phng php tc ng mi, cc ho cht mi c hiu qu

cao hn, r hn v kh thi hn.

102. Th no l mc xi mng?

Xi mng c nhiu mc khc nhau: 200, 250, 300, 400, 500 v 600. Mc

xi mng ch ti trng (tnh bng kg lc/cm2) m xi mng ho rn c th

chu c khng b bin dng sau 28 ngy t khi trn vi nc.

103. nh gi cht lng xng nh th no?

Xng dng cho cc loi ng c thng dng nh t, xe my l hn

hp hirocacbon no th lng (t C5H12 n C12H26). Cht lng xng c

nh gi qua ch s octan l phn trm cc ankan mch nhnh c trong xng.

Ch s octan cng cao th cht lng xng cng tt do kh nng chu p lc

nn tt nn kh nng sinh nhit cao. n-Heptan c coi l c ch s octan

bng zero cn 2,2,4-trimetylpentan c quy c c ch s octan bng 100.

Cc hirocacbon mch vng v mch nhnh c ch s octan cao hn cc

hirocacbon mch khng nhnh. Xng c ch s octan thp nh MOGAS 83

thng phi pha thm mt s ph gia nh tetraetyl ch (C2H5)4 hoc lu

hunh. Cc ph gia ny gip lm tng kh nng chu nn ca nhin liu

nhng khi thi ra khng kh gy nhim mi trng, rt hi cho sc kho con

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ngi. Hin nay, Vit Nam ch yu dng xng A90 hoc A92 l loi xng

c ch s octan cao - nhng loi xng ny khng cn phi thm cc ph gia

nn c hi v t gy nhim mi trng.

104. Bnh cha chy hot ng nh th no?

Kh CO2 khng chy v khng duy tr s chy ca nhiu cht, nn

ngi ta dng nhng bnh to kh CO2 dp tt cc m chy. Tuy nhin,

mt s kim loi c tnh kh mnh, th d Mg, Al,... khi t nng chy c

trong kh CO2:4 0

2CO 2Mg C 2MgO+

+ +

105. t n c s dng trong nhng ngnh kinh t quc dn no ?

t n l mt ho cht c rt nhiu cng dng. N c s dng trong

nhiu ngnh kinh t quc dn nh giao thng vn ti, cng nghip, nng

nghip, sn sut hng tiu dng v nht l lm nguyn liu trong cng nghip

ho cht.106. t n c sn xut t khi no?

Cui th k 19, t n (c trong thnh phn chnh l CaC2) mi ch

c sn xut 12 nc trn th gii. Thi gian ny, t n ch yu dng

thp sng. Da vo cc phn ng sau:

CaC 2H O Ca(OH) C H2 2 2 2 2+ +

5C H O 2CO H O2 2 2 2 22+ +

Cho n nm 1911 vn cn ti 965 thnh ph s dng t thp sng

ng ph vo ban m.

Trong nhiu nm trc y, nc ta, t n c s dng thp

sng trong cc hm l khai thc v vn chuyn than. Ng dn mt s vng

ven bin dng t n vo vic thp sng nh bt c, tm do dng ca

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ngn n t tng ng vi bng in c cng sut 60 - 80 W. nng thn

nc ta, trong nhiu nm trc y ngi ta cng dng t n thp sng

trong nhng dp c nh m hoc l tt.

107. n x oxi - axetilen dng lm g?

Kh axetilen sinh ra khi cho t n tc dng vi nc c dng lm

nhin liu trong n x oxi - axetilen hn ct kim loi do nhit ngn la

c th ln ti 30000C.

sn xut c mt chic xe p ngi ta phi dng ti 3 kg t n.

Vic hn, ct kim loi bng n x oxi - axetilen c s dng khi ng

mi hoc sa cha cc con tu sng, bin hay xy dng, sa cha cc cy

cu, cc cng trnh xy dng.

Khi cn ct, ph cc con tu b h hng tn dng st, thp c

phc v cho ngnh luyn cn thp ngi ta cng dng n x oxi - axetilen.

108. Kh axetilen c dng lm nguyn liu sn xut cc

cht hu c nh th no?

Khi cng nghip ch bin ho hc du m cha pht trin (cho n

khong nm 1950) th kh axetilen sn xut t t n l nguyn liu chnh

ca cng nghip sn xut cc hp cht hu c.

+ Ngi ta cho kh axetilen tc dng vi kh hiroclorua c vinyl

clorua, sau trng hp vinyl clorua thnh polivinyl clorua.

C H CH + HCl CH2 = CH - Cl

n CH2 = CH - CH2 - CH -

Cl Cl n

Polivinyl clorua (PVC) c coi l cht do vn nng. PVC dng

sn xut ra mng mng, bao b, da gi, thng ng ho cht, si chu ho

51

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Xc tc

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cht, cc cu kin xy dng... sn xut 1 tn PVC phi dng t 17 - 2 tn

t n.

+ Cng trn c s cho kh axetilen tc dng vi kh hiroclorua ngita c cc cng ngh tip theo chuyn i thnh butadien sn xut cao su

nhn to v hng lot monome c gi tr cng nghip nh acrilonitril,

vinylaxetat, este ca axit acrylic,...

Trng hp vinylaxetat ri thu phn ngi ta thu c polivinyacol. T

polime ny ko thnh si bn, p, chu c ho cht v thi tit, c ht

m cao c gi l vinylon. Nh vy axetilen l nguyn liu quan trng

gii quyt tt vn mc.109. Kh axetilen c dng sn xut mui than nh th no?

Ngi ta cn dng kh axetilen t t n sn xut mui than gi l

mui axetilen.

Sau khi loi b cc tp cht, kh axetilen c cha vo bn ln ri

dng nhit cao phn hu axetilen to ra cacbon (C) tinh khit. Mui

axetilen l nguyn liu cao cp dng cho cc ngnh in t, sn, mc in, ch

to thp cng, chi than, ch bin cao su,... Ngnh sn xut pin tiu th rtnhiu mui than, bnh qun sn xut 1 triu chic pin R20 phi cn t 2,7

3 tn mui than axetilen. Nh my t n Trng Knh (Hi phng) l cs u tin trong nc sn xut mui than axetilen cung cp cho ngnh pin

v cc ngnh kinh t khc.

110. Trong nng nghip t n dng lm g?

Trong nng nghip, t lu ngi ta dng t n rm qu xanh,

kch thch qu mau chn v chn ng lot cc kho, thng dng rm

da, chui, c chua... vo dp cui ma ng, u ma xun.

Ngi ta x l nn cy da bng t n, cy da s cho qu to ng

u, thm ngon, t l ng cao v nht l lm cho da ra hoa kt qu tri v.

t n cn dng sn xut phn m canxi xinmit (CaCN2) dng

bn cho cc loi cy trng nh la v nht l bng. Hng nm hng DENKA

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ca Nht Bn dng t 300.000 n 500.000 tn t n xn xut phn bn

canxi xianamit.

Mt sn phm ph na m ngnh sn xut t n l kh cacbon oxit(CO). l mt kh cng nghip c gi tr, c th dng ch bin ho hchoc lm nhin liu:

CaO + 3C CaC2 + CO

vi sng than cc

111. Cu to v nguyn tc hot ng ca pin mt tri th no?Ngi ta dng cht liu l nhng t bo silic lm pin mt tri (pin

quang hc). T mt tinh th silic, ngi ta ct ra thnh phin nh, phin ny

c tnh dn in N (m). Trn b mt c dn lp tp cht Bo (B) c tnh dn

in P (dng). Gia P - N c lp phn cch mng. Trn b mt hai lp P - N

c gn in cc dn in ra ngoi.

Nguyn tc hot ng: Lp P c nhng l rt nh nh sng chiu ti

lp N. Cc tia nng cung cp nng lng vo lp N khin v s electron tch

ra khi nguyn t lp silic khuych tn v tch t in cc ( - ) hnh thnh

in tch m. Cn lp P do tc dng ca nh sng lun to thm nhng in

tch dng v tch t bn cc ( + ). Nu khp 2 mch in cc s c dng

in.

112. Lm nn mu nh th no?

Ngy t (tt dng lch v m lch) nu chng ta c hng nn vi ngn

la lung linh, mu sc n giao tha th hay bit my.

Xin mch bn cch lm ra nhng cy nn mu. Thn nn mu , ngn

la cng c mu . Thn nn mu xanh, ngn la cng c mu xanh,... v

cn to ra mi thm quyn r na.

Cch lm:

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l in


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Thn nn lm bng parafin, c th mua parafin ti cc ca hng ho

cht hoc mua loi nn r tin ly parafin.

Cht to mu cho thn cy nn l nhng cht mu c th tan trongparafin nng chy nh metyl xanh (mu xanh) auramin (mu vng), rodamin,

eosin (mu ),...

Cng c th to mu cho thn cy nn bng cch n gin hn l dng

phn mu bi ln cy nn.

Bc nn lm bng si bng, si lanh,... khng dng si tng hp.

bc chy khng c tn cn tm bc bng dung dch natri borat hoc natriphotphat ri phi kh.

Cht to mu cho ngn la l cc mui v c.

Ho tan ring tng mui v c vo nc c dung dch bo ho.

Tm bc vo dung dch mui bo ho ri phi kh.

Khi chy ngn la s c mu nh sau:

KCl hay KNO3 : Mu tm (bi K+

) NaCl hay NaNO3 : Mu vng (bi Na+)

LiCl hay LiNO3 : thm (bi Li+)

CaCl2 hay Ca(NO3)2 : gch (bi Ca2+)

BaCl2 hay Ba(NO3)2 : Xanh nn chui (bi Ba2+)

CuCl2 hay CuSO4 : Xanh da tri (bi Cu2+)

113. Lm nn thm nh th no? Cht thm: Dng nc hoa hay tinh du c th ho tan vo parafin

khi nng chy.

Khi chun b xong parafin lm thn cy nn c mu v c mi

thm; bc nn tm dung dch mui v c to mu cho ngn la, ta tin hnh

khun c thnh cy nn.

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Khun nn c th dng cc ng bng kim loi hay cht do c sn

hoc g bng st ty.

t bc vo khun, sao cho ng tm ri c nh pha di v phatrn. Nu chy parafin ri vo khun. ngui v tho khun.

Parafin nng chy 50 - 550C nhng cn un qu nhit ny.

Thng khun 60 - 650C. Nu khun nhit thp hn, parafin s

ng cng nhanh v b mt nn khng nhn. nhit cao hn, nht

qunh ca parafin thp lm n d chy qu cc khe h ca khun.

C th c cy nn c nhiu mu, mi khc mt mu hoc c vn bng

cch c tng khc hay trn ln cc mu.

Cng c th dng mt cht va to mu cho thn cy va to mu

cho ngn la. Th d nh:

+ Nn xanh l cy: Dng Crom (III) oxit. Mu ngn la cng xanh l

cy do ion Cr3+. iu ch cht ny bng cch nhit phn mui amoni icromat

hoc nung nng natri icromat vi lu hunh.

+ Nn vng: Dng natri cromat lm mu cho thn nn. Ngn la cng

vng nh ion Na+.

Trong nhng ngy l ln chng ta c xem nhng mn pho hoa rc

r, mun mu. Pho hoa cng c ch to theo nguyn tc trn.

114. Th no l hiu ng nh knh ?

Chng ta rt hay nghe thy cm t Hiu ng nh knh, vy hiu ng

nh knh l g ? l hin tng lm cho Tri t m ln bi kh CO2. Kh

CO2 trong kh quyn ch hp th mt phn nhng tia hng ngoi (bc x

nhit) ca mt tri v cho cc tia c sng t 50.000 n 100.000 A0 i qua

n mt t. Nhng bc x nhit pht ngc li t mt t c bc sng trn

140.000A0 b kh cacbonic hp th mnh v pht tr li tri t lm Tri t

m ln. V mt hp th bc x, lp CO2 trong kh quyn tng ng vi

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lp thu tinh cc nh knh dng trng cy, x lnh. Do hin tng

lm Tri t m ln bi kh CO2 c gi l Hiu ng nh knh.

Ngi ta cho rng nu trong kh quyn ca hnh tinh chng ta khng clng kh CO2 th nhit mt t thp hn hin ti l 21 0C. Ngc li nu

CO2 tng gp i so vi hin ti nn nhit s tng thm 40C. sao Kim,

lng CO2 gp 60.000 ln Tri t nn nhit trung bnh ca sao Kim l

4250C.

Ch rng nhit mt t tng ln 10C nh hng bt li cho

sn xut lng thc ca th gii. Nguyn nhn ca s tng hm lng CO2

trong kh quyn l vic s dng nhin liu trong nh my nhit in v cc

nh my khc, l vic ph rng. V vy v li ch chung hy bo v ly rng -

l phi ca Tri t !!!

115. Tng ozon ang b suy gim nh th no ?

Trn tng cao ca kh quyn, cc mt t gn 25 km c mt lp ozon

dy, gi l tng ozon. N c tc dng ngn khng cho tia cc tm chiu trc

tip xung Tri t.

Do phn ng: 22 3

O h 2O

O O O

+

+ h c : 1600 2400 A0

Tuy nhin gn y cc nh khoa hc pht hin thy mt s khu vc

tng ozon b bo mn, thm ch c ch b thng - gi l thng tng ozon.

Tng ozon b thng s khng cn tc dng ngn tia cc tm - ngha ltia cc tm s chiu trc tip xung Tri t gy ra nhiu bnh ngoi da cho

con ngi v ng vt (v d nh ung th da,)

Nguyn nhn do mt s kh nh: freon (CFC), cc oxit nit. Cc freon,

l cc hp cht Clorofloro cacbon, v d nh CFCl3, CF2Cl2, c dng rng

ri lm cht y trong bnh phun, chy gy lnh trong t lnh v my iu ho

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nhit v cht gy xp cho cht do. Di tc dng ca cc bc x mt tri

( : 1900 2250A0 ) chng thc y qu trnh bin i O3O2

116. Mn khi git ngi xy ra u ?Ngy 5 thng 12 nm 1952, nc Anh (nc c mnh danh l x s

ca sng m) ti Lun n xy ra s kin mn khi git ngi lm

chn ng th gii. Vic gim st mi trng cho thy hm lng kh SO 2cao

ti 3,8mg/m3, gp 6 ln v nng bi khi ln ti 4,5mg/m3 gp 10 ln so

vi ngy thng. Dn trong thnh ph thy tc ngc, kh th v ho lin tc.

Ch trong vng 4, 5 ngy c hn 4000 ngi cht trong phn ln l tr

em v ngi gi, hai thng sau li c trn 8000 ngi na cht.

Nguyn nhn ca mn khi git ngi thnh ph Lun n l do

khi than ca cc nh my quyn vo vi sng m bui sm ma ng gy

ra.

117. Kh clo c dng lm v kh u v khi no ?

l x chiu ngy 24 - 4 - 1915 (th chin th nht 1914 - 1918) gia

2 ngi lng c tn l Steenstraat v Poel Kappelle (nc B) xut hin mt

m khi mu vng lc xut pht t phng tuyn ca qun c bay l l cch

mt t 1 mt theo chiu gi tin dn n phng tuyn qun Php. l khi

ca 150 tn clo cha trong 5830 thng iu p va c cc binh s ca trung

on qun tin phong 35 v 36 c th vo khng kh. Mi lm pht sau, b

binh c c trang b c bit bm theo m khi clo tn cng thng vo

c im Php. S tc ng ca kh c tht v cng gh gm. Hng trm binh

s Php hn lon chy ngc v pha sau tm khng kh th. Khi qun c

ti ni h trng thy nhiu xc cht vi gng mt xanh nht nm la lit bn

nhng ngi hp hi, c th co git d di, ming a ra mt cht dch mu

vng nht. Kt qu l tuyn phng th ca qun Php b ph v v kh clo

git cht 3000 ngi v lm 7000 ngi b thng.

118. Axit xitric c u ?

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Trong thin nhin axit xitric c trong cc loi qu chua (chanh, tai

chua), trong mt s loi l cy (bng, thuc l, thng).

Axit xitric c cng thc ho hc l

Tinh th c mu trng, tnc = 1530C, d tan trong nc. Axit xitric l sn

phm trung gian quan trng ca qu trnh trao i cc axit tricacboxylic trong

c th.

Axit xitric dng lm cht bo qun, cht to v trong cng nghip thc

phm. Trong nghip thc phm, axit xitric chim hng u trong s cc axit

hu c. Axit xitric cn c dng trong dc phm v cc cht ty git

119. Vin kim cng ln nht ngn h nm u ?

Cc nh thin vn M va pht hin ra mt ngi sao kim cng c

ng knh 1500 km, cch Tri t khong 50 nm nh sng c gi l

Lucy

Lucy hay BPM37093 c li c, nng ca mt ngi sao c tng

chiu sng ging nh mt tri. Tuy nhin, ngi sao c ny ngui, v co li.

Cc nh thin vn thng gi n l: Sao ln trng. Gn y cc nh thin

vn pht hin ra rng: cc v sao khng ch to sng m cn ngn vang

ging nh mt chic chung khng l. o nhng rung ng ny, ngi ta c

th nghin cu thnh phn bn trong ca Lucy. T , h pht hin ra rng

cacbon bn trong Lucy cng li to nn khi kim cng ln nht ngn h.

T , cc nh khoa hc phng on rng, Mt Tri ca chng ta,

khi tn li trong vng 5 t nm na s kt tinh to ra vin kim cng khng l

trung tm Thi dng h.

Metcalfe ni: Mt Tri ca chng ta s tr thnh mt vin kim cng

vnh hng.

58

HOOC CH2

COOH

CH2 COOH

OH

C


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120. Ai pht minh ra thp khng g ?

l nh khoa hc Anh H.Brearley. Trong chin tranh th gii ln th

nht ng c giao nhim v nghin cu ci tin v kh, c bit l vn nng sng b mi mn rt nhanh. ng th pha crrom vo thp, song cha

va nn bn qung vo ng st g ngoi phng th nghim.

Rt lu sau ng thy mu th y vn sng lng lnh trong khi ng thp

g ht c.

Nm 1913 H.Brearley nhn c bng pht minh c quyn ca

nc Anh. ng sn xut thp khng g trn qui m ln v tr thnh ngi

cha ca thp khng g

121. Ai c trao gii Nobel ho hc u tin ?

l nh ho hc H Lan Jacobus H.Vant Hoff (1852 - 1911) ng

c nhn gii Nobet vo nm 1901. Cho n nm 2005 c 148 nh khoa

hc c gii Nobel ho hc.

122. Ai c gii Nobel ho hc nm 2004 ?

Hai nh khoa hc ngi Israel Aaron Ciechanover v Avram Hershko

v mt nh khoa hc ngi M Irwin Rose, nhn gii Nobel ho hc 2004

vi s tin 1,36 triu USD cho cng trnh ca h lin quan ti cch thc c

th tm ra nhng protein khng thch hp tiu dit v t bo v mnh khi

bnh tt.

T u thp nin 1980, ba nh khoa hc trn pht hin ra mt trong

nhng qu trnh c tnh chu k quan trng nht ca t bo: qu trnh thoi ho

protein, qu trnh ny c kim tra ti tng chi tit, protein no khng thch

hp s c ng du bng mt phn t c bit c gi l n hn thn

cht. Nhng protein c dn nhn cht ny s c a vo gi rc ca

t bo gi l proteasomes, y chng b phn ra tng mnh nh v b hu

dit. Phn t lm nhn ny c gi l ubiquitin.

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Khi vic thoi ho protein ny din ra khng ng, con ngi s b ung

th. Kin thc v protein iu tit ubiquitin s gip ngi ta bo ch thuc

chng mt s loi bnh.123. Ai c gii Nobel ho hc nm 2005 ?

l 3 nh ho hc : Robert H.Grurbbs (M)

Richard Schorock (M) v Yves ChanVin (Php). Ba ng pht trin

phng php hon v trong tng hp hu c. Trong phn t cht hu c, cc

nguyn t C lin kt vi nhau v lin kt vi cc nguyn t ca cc nguyn t

khc theo mt trt t nht nh. Trong phn ng hon v, cc lin kt i b

ph v hoc to thnh do s i ch gia cc nhm nguyn t nh nhng cht

xc tc c bit. Phng php hon v c nhiu u im vt tri so vi cc

phng php tng hp c nh t phn ng hn, cn t nguyn liu hn, to ra

t cht thi hn Gii Nobel ho hc nm 2005 gm tm sc 1,3 triu USD

(chia u cho 3 ngi) huy chng Nobel v bng chng nhn.

124. Ng v l nhng v no v do cht g sinh ra ?

Ng v gm: chua, ngt, ng, cay, mn.

- V ngt do ng sinh ra, ng l ngun nhit lng ch yu cho c

th con ngi. V ngt c tc dng bi dng c th, gii c, lm gim s

cng thng cho c bp.

- V chua do axit hu c sinh ra. V chua c tc dng kch thch s

thm n, tng sc mnh cho gan, nng cao kh nng hp th photpho, can xi.

- V ng ch yu do kim hu c trong n sinh ra, c tc dng iu

tit gan, thn, li tiu.

- V cay ch yu do kim t sinh ra. V cay kch thch s co bp d dy,

tng cng s tit dch tiu ho.

- V mn ch yu sinh ra t mui n (NaCl). V mn c tc dng gi

cn bng p lc thm thu gia huyt dch v t bo, iu tit qu trnh trao

i mui, nc ca c th.

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125. u tng c s dng nh th no ?

T u tng ngi ta ch bin ra nhiu mn n hp dn nh tng,

u ph, sa u nnhNh

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