Answer to Hodder Review Questions 1

8/9/2019 Answer to Hodder Review Questions 1

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Answers to Topic 1 Review questions

1 a) Labelled axes (1); accurate plot (1); smooth curve (1).

b) Three half-lives = 40 × 103 s (); half-life of !rst order reactio" i"depe"de"t of

i"itial co"ce"tratio" (1).

c) #ethod of calculati"$ $radie"t (1); values for $radie"ts (); u"its% mol

dm&3

s&1

(1).

d) 'xes (1); accurate plot ith strai$ht li"e (1).

k = 1. × 10&* (1); s&1 (1).

2 a) 'xes (1); plot a"d curve (1).

+alf-life from 0 × 10&3 mol dm&3% 3., × 103 s (1)

+alf-life from 1 × 10&3

mol

dm−3% ., × 103

s (1)

Loer starti"$ co"ce"tratio" hi$h half-life (1).

b) Ta"$e"ts dra" (1); $radie"ts calculated (1); co"ce"tratio" u"its i"cluded (1).

c) /ptio"s%

lot a co"ce"tratio"time $raph a"d tae a series of readi"$s from the $raph tosho that it taes the form y = x

plot 12't a$ai"st time to $et a strai$ht li"e if the reactio" is seco"d order5

here 't is the co"ce"tratio" at time t

plot lo$(rate) a$ai"st lo$(co"ce"tratio") to $et a $raph ith $radie"t .

6hoice of method (1); plot (); expla"atio" ().

3 a) +/(a7) 8 +8(a7) 8 9&(a7) → +/(l) 8 9(a7) (1).

b) :ate = k+/(a7)9&(a7) ()

c) eco"d order (1)

d) The !rst step (1); hich i"cludes the to species hich feature i" the rate

e7uatio" (1).4 a) i) 6ha"$i"$


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used up the iodi"e produces a deep blue-blac colour ith the starch i"dicator

(1).

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© ! "i## and A! "unt 200$ %de&ce# '(eistr* for A2


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b) 6ompletio" of table (3)%

Temperature, T /K 288 292.5 299 308 315

Time, t, for the blue colour to appear/s 10.0 7.0 5.0 3.5 2.5

ln (1/t) −2.30 −1.95 −1.61 −1.25 −0.92

1/T /K 1 0.00347 0.00342 0.00334 0.00325 0.00318

lot of $raph of l" (12t) a$ai"st 12T ith appropriate scales a"d accurate li"ear plot

(3).

Aradie"t = −410

B (1) = R

Ea−

Ea = 3* D mol &1 (1)

c) The catal@st provides a" alter"ative reactio" patha@ ith a loer activatio"

e"er$@ (1). /"e possible alter"ative route is that he" the catal@st is prese"t the

iro"(999

) io"s oxidise iodide io"s to iodi"e (1) a"d that peroxodisulfate( E9

) io"s the"oxidise the resulti"$ iro"(99) io"s bac to iro"(999) thus re$e"erati"$ the catal@st.

(1). erhaps the "e$ative peroxodisulfate( E9) io"s react more readil@ ith positive

iro"(99) io"s tha" ith "e$ative iodide io"s (1).

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1 a) 't 0 B ater is solid a"d the atoms

are hi$hl@ ordered. (1); The cr@stalsare "ot disrupted b@ molecular

moveme"t (1).

b) The rises i" e"trop@ at T 1 a"d T

correspo"d to the cha"$es of state%

melti"$ a"d vaporisatio" (1).

There is a $reater i"crease i"

disorder he" molecules separate

from a li7uid a"d tur" to $as tha"

he" molecules melt (1); because of

the much $reater freedom ofmoveme"t of molecules i" the $as

phase (1).

c) Fater a"d steam are i" e7uilibrium

(1);

at 33 B a"d 1 atmosphere pressure

so there is "o te"de"c@ for the

cha"$e to $o i" either directio" (1).

d) ∆Stotal = ∆Ss@stem 8 ∆Ssurrou"di"$s (1)

i"ce GStotal = 0 D mol&1 a"d

∆Ssurrou"di"$s = &∆ H 2T (1)it follos that ∆Ss@stem = &∆ H 2T (1)

∆Ss@stem =B 3-3

molD141 1−. (1)

= 0.110 D mol&1 B &1

= 110 D mol&1 B &1 (1)

2 a) 'l/3(s) 8 36(s) → 'l(s) 8 36/($)

(1)

b) Total e"thalp@ cha"$e of formatio" of

products = 3 × (&111 D mol&1)

= &333 D mol&1 (1)Total e"thalp@ cha"$e of formatio" of

reacta"ts = &1,,H D mol&1 (1)

/verall e"thalp@ cha"$e for the

reactio"

= (&333 D mol&1) & (&1,,H D mol&1)

= 8133, D mol&1 (1)

c) Total e"trop@ of products

= ( × .3 D mol&1 B &1) 8 (3 × 1H D

mol&1 B &1)

= ,*1 D mol&1 B &1 (1)

Total e"trop@ of reacta"ts

= *0.H D mol&1 B &1 8 (3 × *. D mol&1

B &1

)= , D mol&1 B &1 (1)

/verall e"trop@ cha"$e of the s@stem

= ,*1 D mol&1 B &1 & , D mol&1 B &1 (1)

= *3 D mol&1 B &1

d) i) I"trop@ cha"$e of the

surrou"di"$s

=B H

mol D00033,1 1−−

= &443

D

mol&1

B &1 (1)

The total e"trop@ cha"$e

= *3

D

mol&1

B &1 & 443

D

mol&1

B &1 (1)

= &3H00

D

mol&1

B &1

ii) The reactio" is "ot feasible at H

B because the total e"trop@

e"er$@ cha"$e is "e$ative (1).e) The reactio" becomes feasible he"%

∆Ss@stem &T

H reactio∆ J 0

T ∆Ss@stem J ∆ H reactio" (1)This Kust happe"s he" T =

11

1

B molD0.*3

molD133,−−

−

= H B (1)

f) :eactio"s betee" solids are slo.

The reactio" has to be ver@ hi$h forit to proceed at a measurable rate

(1).

3 a) i) ∆Ssurrou"di"$s =B H

mol D000*1H 1−+

= 814

D

mol&1

B &1 (1)

∆Stotal = 8 D mol&1 B &1 8

14

D

mol&1

B &1

= 814

D

mol&1

B &1 (1)

ii) The total e"trop@ cha"$e is

positive so the reactio" is feasible(1).

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iii) 't H B the activatio" e"er$@ of

the reactio" is too hi$h (the bo"ds

i" the molecules are too stro"$)

(1) a"d the e"er$@ of collisio"s

betee" molecules too lo for the

reactio" to happe" at a

measurable rate (1).

b) 9" the reactio" formi"$ 6/ a"d

steam5 .* mol $ases react to form 3

mol of $as (1). This i"creases

disorder so that the e"trop@ cha"$e

is substa"tiall@ positive (1).

9" the reactio" formi"$ soot5 mol

$ases react to form a" ordered solid

a"d mol $as (1). /verall there is

little cha"$e i" e"trop@ (1).

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4 a)

b) ∆ H solutio"6a6l(s)

= &(&* D mol&1) & 1,* D mol&1

8 ( × &340 D mol&1) (1)

= &H D mol&1

(1) for H; (1) for si$" a"d u"its

c) The 6a8 io" has a hi$her char$e a"d a lar$er radius tha" Li 8. The hi$her char$e

ill te"d to mae its electro" de"sit@ $reater tha" Li8 (1); but its lar$er radius ill

te"d to mae its electro" de"sit@ less tha" Li8 (1).

d) Fater molecules are polar ith a δ8 char$e betee" the + atoms a"d a δ& char$e

o" the / atom (1). The δ8 char$e attracts a"io"s a"d the δ& attracts catio"s (1);

so h@dratio" is a" exothermic process a"d the h@dratio" e"thalpies of both a"io"s

a"d catio"s are "e$ative (1).

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1 a) K c =

)dmmol(0.01)dmmol(0.01

)dmmol(0.0-33

3

−−

−

×

(1)

= 4H (1); "o u"its (1)

b) i) The 7ua"tit@ of iodi"e that has

reacted

= 0.003 mol dm&3

This reacts ith 0.003

mol

dm&3

h@dro$e" a"d produces 0.00,

mol

dm&3 +9.

o the "e co"ce"tratio"s are%

+($) = 0.01 mol dm&3 (1); a"d

+9($) = 0.0,

mol

dm&3 (1).ii) ubstituti"$ i" the expressio" for

K c $ives

)dmmol(0.00-)dmmol(0.01-

)dmmol(0.0-,33

3

−−

−

×

(1)

= 4.*

This is ver@ close to the value for

K c calculated i" a). The s@stem is

a$ai" at e7uilibrium (1).c) oubli"$ the h@dro$e" co"ce"tratio"

causes a shift i" the positio" of

e7uilibrium to the ri$ht $ivi"$ more

+9 a"d less iodi"e (1); some5 but "ot

all5 of the added h@dro$e" reacts (1).

2 a) 6o"ce"tratio" =10

1- × 0.*0 mol dm&3

(1)= 0.*

mol

dm&3 (1)

b) 6o"ce"tratio" =100., × 0.01

mol

dm&3 (1)= 0.00,

mol

dm&3 (1)

c) K c = 3

3

dmmol0.00,

dmmol0.*−

−

= 140 (1); "o

u"its (1)

3 a) i) K c = 3

4

(a7)(a7)Me;"

(a7)(a7)Me;"++

++

()

ii) K c has "o u"its (1); theco"ce"tratio" terms ca"cel (mol

dm&3)3 appears o" the top a"d the

bottom of the expressio" for K c

(1).

b) i) The reciprocal of the value $ive"

i" the 7uestio" (1)% K c = 1 × 10&10

(1).

ii) The s7uare root of the value $ive"

i" the 7uestio" (1)% K c = 1 × 10*

(1).4 a) 't e7uilibrium the forard a"d

bacard reactio"s happe" at the

same rate so that overall there is "o

cha"$e (1). Nitro$e" a"d h@dro$e"

react to form ammo"ia as fast as

ammo"ia decomposes bac to

"itro$e" a"d h@dro$e" (1).

b) i) #ole fractio"s% N+35 0.13 (1);

+5 0.,** (1); N5 0.0H (1)

ii) artial pressures% N+35 1.3

atm;

+5 ,.** atm; N5 .0H atm ()

iii) K p = 3+N

N+

)(

)(

3

pp

p

× (1)

= 3.0 × 10&3 (1); atm& (1)

c) ∆Stotal = ∆Ss@stem T

H reactio"∆ (1)

∆ H is "e$ative a"d so the totale"trop@ cha"$e $ets smaller as T

rises (1).

∆Stotal = R l" K (1)

This mea"s that K p $ets smaller as T

rises (1).

's a result5 the mole fractio" of

ammo"ia decreases a"d the mole

fractio"s of "itro$e" a"d h@dro$e"

i"crease as T rises (1).

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1 a) K c =($)6l

($)($)6l6l

*

3 (1)

b) K c = 33 dmmol10

1−−

×

= 1* (1)

dm3

mol&1

c) 6l3($) = 6l($) = x (1)

3

dmmol10* −−×

x= O 10&3

mol

dm&3 (1)

x = O 10& mol dm&3 (1)

d) i) ome5 but "ot all5 of the added

6l* decomposes (1) a"di"creases the co"ce"tratio"s of

6l3 a"d chlori"e (1).

ii) 9"creasi"$ the pressure causes

the e7uilibrium to shift i" the

directio" that $ives feer moles

of $as (1); so the co"ce"tratio" of

6l* i"creases hile the

co"ce"tratio"s of 6l3 a"d

chlori"e decrease (1).

iii) :aisi"$ the temperature causesthe e7uilibrium to shift i" the

directio" that is e"dothermic (1);

so the co"ce"tratio" of 6l*

decreases hile the

co"ce"tratio"s of 6l3 a"d

chlori"e i"crease (1).

e) i) 6ha"$i"$ co"ce"tratio"s does "ot

aect the value of K c (1).

ii) 6ha"$i"$ the pressure does "ot

aect the value of K c (1).

iii) K c i"creases (1). Mor a"

e"dothermic reactio" the value of

K c $ets lar$er as the temperaturerises (1).

2 a) 6hemical e7uilibrium is d@"amic (1);

o" a molecular scale there is

co"sta"t cha"$e ith opposi"$

reactio"s ca"celli"$ each other out

(1). +oever5 the overall

macroscopic eect is that "othi"$

appears to be cha"$i"$ he" the

s@stem is at e7uilibrium (1).

b) K c does "ot var@ ith co"ce"tratio"(1). +oever5 it is true that addi"$

more of a reacta"t to a s@stem at

e7uilibrium mea"s that the mixture

is "o lo"$er at e7uilibrium (1); some

of the added chemical reacts a"d

more products form u"til the s@stem

is a$ai" at e7uilibrium (1).

c) 'ddi"$ a catal@st does "ot aect the

value of K c (1). 't a co"sta"t

temperature5 the @ield of product ate7uilibrium is "ot cha"$ed b@ addi"$

a catal@st (1); hoever5 ma"@

processes are so slo that the@ "ever

reach e7uilibrium i" the abse"ce of a

catal@st5 so i" that se"se a" added

catal@st i"creases the @ield b@

e"abli"$ the reactio" mixture to

reach e7uilibrium (1).

d) This is true if the reactio" to mae

products is e"dothermic (1). 9f the

reactio" is exothermic5 the" the

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e7uilibrium @ield of product falls as

the temperature rises (1). +oever5

as ith catal@sts5 raisi"$ the

temperature ca" i"crease the @ield of

a product b@ alloi"$ a reactio"

mixture to reach e7uilibrium that

reacts too slol@ at room

temperature (1).

e) ' reactio" is feasible i" the

thermod@"amic se"se if the total

e"trop@ cha"$e for the process is

positive (1). 'ddi"$ a catal@st

speeds up the rate of reactio" but

ca""ot cha"$e the feasibilit@ of a

reactio" at a particular temperature

(1). /"l@ if the reactio" is "ot $oi"$

because it is i"eticall@ i"ert ca" a

catal@st e"able a reactio" to happe"

at a particular temperature (1).

3 a) K p = /+6+

3+6/

4

)(

pp

pp

×

×

()

b) i) K p does "ot cha"$e (1).

ii) K p i"creases (1).

iii) K p does "ot cha"$e (1).

c) i) 6o"ce"tratio" of products

decreases a"d the co"ce"tratio"

of reacta"ts i"creases (1).

ii) 6o"ce"tratio" of products

i"creases a"d the co"ce"tratio" of

reacta"ts decreases (1).

iii) 6ompositio" of the e7uilibrium

mixture does "ot cha"$e (1).

4 a) 4N+3($) 8 */($) 4N/($) 8

,+/($) ()

b) 9" theor@ the @ield of N/ at

e7uilibrium is hi$h if the

temperature is lo (1) a"d the

pressure lo (1); addi"$ excess

ox@$e" also favours the co"versio" of

ammo"ia to N/ (1).

c) There is a" excess of ox@$e" (eve"

thou$h o"l@ a !fth of the air is

ox@$e") (1). The temperature has to

be hi$h because reactio" o"l@

happe"s at a practicable rate if the

catal@st is hot (1). :aisi"$ the

pressure compresses the $ases a"d

this i"creases the mass of material

Poi"$ throu$h

the reactor a"d he"ce the mass of

product produced i" a $ive" time

from a $ive" piece of pla"t (1).

(The chose" pressure also depe"ds

o" the price of plati"um. Fori"$ at

hi$her pressures i"creases the ear

o" the catal@st a"d shorte"s the life

of the catal@st $au>es.)

d) The $ases Po throu$h the solid

catal@st $au>es a"d so the catal@st isused co"ti"uousl@ a"d does "ot have

to be recovered from the reactio"

mixture (1).

e) The $ases Po throu$h the catal@st

$au>es so the mixture of product a"d

u"cha"$ed reacta"ts is o"l@ i"

co"tact ith the catal@st for a short

time (1); as soo" as the $ases Po

aa@ from the catal@st reactio" stops

the mixture has time to approach

e7uilibrium but "ot reach

e7uilibrium (1).

f) The hot $ases Po thou$h a heat

excha"$er here the@ tur" ater to

hot steam (1); that ca" be used i"

other processes or to $e"erate

electricit@ (1).

5 a) 9" a simple additio" reactio" tochemical combi"e to form a si"$le

product (1); so all the reacta"t

molecules e"d up i" the product the

atom eco"om@ is 100Q (1); example

(1).

9" a"@ substitutio" reactio" there is

at least o"e other chemical formed i"

additio" to the desired product (1);

example (1).

b) The @ield of a reactio" measures theamou"t of product made compared

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ith the amou"t expected accordi"$

to the bala"ced chemical e7uatio"

(1); the calculatio" of @ield taes "o

accou"t of the other products of the

reactio". (1); it is possible to have a

ver@ hi$h @ield from a reactio" ith a

lo atom eco"om@ (1); example used

to disti"$uish @ield from atom

eco"om@ ().

c) 6ha"$es i" temperature aect both

the rate of reactio" (1); a"d the

compositio" of the e7uilibrium

mixture (1); reactio"s have to $o fast

e"ou$h to produce product from a

chemical pla"t at a" eco"omic rate

(1); i" practice this ca" mea" that

the temperature has to be hi$her

tha" ould otherise be chose" to

maximise the perce"ta$e of product

i" the e7uilibrium mixture. (1);

example explai"ed (1).


1 a) +


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' t@pical buer mixture co"sists of a solutio" of a ea acid a"d o"e of its salts5

for example a mixture of etha"oic acid a"d sodium etha"oate (1); there must be

ple"t@ of both the acid a"d its salt i" the buer mixture (1).

'ddi"$ a small amou"t of stro"$ acid temporaril@ i"creases the co"ce"tratio" of

+8(a7) so the e7uilibrium shifts to the left to cou"teract the cha"$e (1); addi"$ a

small amou"t of stro"$ alali temporaril@ decreases the co"ce"tratio" of +8(a7) so

the e7uilibrium shifts to the ri$ht to cou"teract the cha"$e (1).

The p+ of blood5 for example5 is closel@ co"trolled b@ buers ithi" the "arro

ra"$e .3* to .4*. 6hemists use buers he" the@ a"t to i"vesti$ate chemical

reactio"s at a !xed p+ (1).b) i) +8(a7) =

1. × 10&* mol dm&3 O 3

3

dmmol04.0

dmmol0.0−

−

= 3.4 × 10&* mol dm&3

p+ = 4.* (1)

ii) +8(a7) = 1. × 10&*

mol

dm&3

O3

3

dmmol0,.0

dmmol0,.0−

−

(1) = 1. × 10&* mol dm&3

p+ = 4. (1)

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Answers+ .tereoc(e)istr*

iii) +8(a7) =3

,14

dmmol0.0

dmmol101−

−−

×

= *.0 × 10&1 mol dm&3 (1)

p+ = 11.3 (1)

iv) The cha"$e of p+ is ver@ much less he" addi"$ the alali to a buer solutio"

tha" he" addi"$ it to ater (1).

3 a) tro"$ acid io"ises completel@ i" a7ueous solutio" (1). '" example is

h@drochloric acid% +6l(a7) → +8(a7) 8 6l&(a7) (1)

' ea acid o"l@ io"ises to a sli$ht exte"t i" solutio" (1). '" example is etha"oic

acid%

6+36//+(a7) +8(a7) 8 6+36/&(a7) (1)

b) i) 2 (1)

ii) /+&(a7) = 0.01

mol

dm&3

+8(a7) =3

,14

dmmol010

dmmol101−

−

×

.

= 1 × 101 mol dm&3 (1)

p+ = 1 (1)

c) i) 3* dmmol0.0)10(1.*(a7)4+ −−+ ××= (1)

p+ = 3.3 (1)

ii) Li"e of setch $raph rises at !rst from p+ = 3.3; partl@ levels o throu$h buer

re$io" (1); the" rises to $ive a steepl@ risi"$ curve he" the titre is * cm3 (1)

; half-a@ up the steepl@ risi"$ portio" is above

p+ (1); the curve the" levels o at about

p+ 1 (1).

iii) Th@molphthalei" (1) full colour cha"$e must tae place ithi" the steepl@risi"$ part of the curve (1).

4 a) i) +6l/(a7) +8(a7) 8 6l/&(a7) (1)

ii) K a =+6l/(a7)

(a7)(a7)6l/+ −+ (1)

b) +8(a7) = 10&.43 (1) = 3. × 10& mol dm&3 (1)

K a = 3

33

dmmol0.0*0

)dmmol)(0.0*0dmmol10(3.-−

−−−

× (1)

= 3. × 10& mol dm&3 (1); Rp K a = .4 (1)

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Answers to Topic + Review questions

1 a) To structural isomers ith the

same fu"ctio"al $roups (1);

structures of

1-chloropropa"e a"d

-chloropropa"e (1).

b) ix structural isomers2 E–Z isomers%

o"e ith M o" the 6 atom ith +5

o"e ith the 6l o" that atom5 a"d

o"e ith the Sr o" that atom. The"

each of these ca" have E–Z isomers(,).

c) To E–Z isomers% the E isomer has

the Sr a"d 6l o" opposite sides of

the double bo"d (1)5 hile the Z

isomer has them o" the same side

of the double bo"d (1).

2 a) ' chiral ce"tre is t@picall@ a carbo"

atom ith four diere"t $roups

arou"d it (1); i" $e"eral a molecule

is chiral if it is [email protected]) The mirror ima$e forms or a chiral

molecule ca""ot be superimposed

o" o"e a"other (1); the@ have

opposite eects as the@ rotate the

pla"e of pla"e-polarised li$ht (1).

c) /"l@ 6+36+/+6//+ is chiral a"d

ca" exist as to optical isomers

(1); the other to compou"ds both

have to h@dro$e" atoms o" the

ce"tral carbo" atom .d) ' racemic mixture co"tai"s e7ual

amou"ts of the to optical isomers

(1); the to isomers rotate the

pla"e of pla"e-polarised li$ht

e7uall@ but i" opposite directio"s

so their eects ca"cel (1).

e) i) 613+1/3N (1)

ii) There is o"e chiral carbo" atom%

(1)

3 tereoisomerism i"volves molecules

ith the same molecular formula (1);

a"d the same structural formula (1);

but diere"t three-dime"sio"al

shapes (1); i" hich their atoms

occup@ diere"t positio"s i" space

(1).

There are to forms of

stereoisomerism.

E–Z (cis/trans) isomerism (1); hichoccurs pri"cipall@ i" ale"es a"d

other compou"ds ith 6=6 double

bo"ds (1).

9" E–Z isomerism5 the Z-isomer has

atoms5 attached to the 6 atoms of the

double bo"d5 ith hi$her atomic

"umber (1) o" the same side of the

double bo"d (1).

9" the E-isomer5 atoms attached to the

6 atoms of the double bo"d ithhi$her atomic "umber are o" opposite

sides of the double bo"d (1). '"

example of E–Z isomerism is 15-

dibromoethe"e.

Named structures of the E a"d Z

isomers ().

/ptical isomerism (1) i"volves "o"-

superimposable mirror ima$es (1). 9"

most cases5 this re7uires the

molecules to possess a 6 atom ithfour diere"t atoms or $roups

attached to it (1).

These mirror ima$es are labelled (8)

a"d (−) forms (1).

The (8) form rotates pla"e-polarised

li$ht clocise (1) a"d the (−) form

rotates pla"e-polarised li$ht

a"ticlocise (1).

' "amed example of optical

isomerism (1); e.$. ala"i"e or

bromochloroPuorometha"e.

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ia$ram shoi"$ structures of the

optical isomers of the example

su$$ested as mirror ima$es (1).

'"@ 1* of these or other le$itimate

poi"ts

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Answers, 'arbon*# co)pounds

Answers to Topic , Review questions

ReactantReagent Organic product

Name Displayed formula

CH3CH2CHO Tollens’ reagent propanoic acid (1

(1

CH3CH2CHO Cr2O72!"H# (1 propanoic acid

(1

CH3CH2CHO $i%lH4 propan&1&ol (1

(1

2 a) 610+1,/ (1)

b) i) 6arbo"carbo" double bo"d as i" a" ale"e (1); aldeh@de $roup (1).

ii) Beto"e $roup (1).

c) i) The blue rea$e"t $ives a" ora"$e-bro" precipitate (1) ith citral; but "ot

ith β-io"o"e (1).

ii) The rea$e"t $ives a bri$ht ora"$e precipitate (1); ith citral a"d ith β-io"o"e

(1).

iii) The rea$e"t $ives a pale @ello precipitate (1) ith β-io"o"e; but "ot ith

citral (1).

d) i) The structure sta@s the same except that the eto"e $roup is reduced to a

seco"dar@ alcohol; the side chai" attached to the ri"$ becomes

6+=6+6+/+6+3 (1).

ii) The structure sta@s the same except that the aldeh@de $roup is oxidised to a

carbox@lic acid $roup 6//+ (1).

e) i) Soth compou"ds have E–Z isomers (1).

ii)

Z -citral (1)

iii) Neither compou"d has a chiral ce"tre a"d so "either has optical isomers (1).

3 a) F% empirical formula 6+5 molecular formula 64+ (1); could be but-1-e"e or but-

-e"e (1); because both $ive -bromobuta"e he" the@ add +Sr.


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Answers- 'arbo&*#ic acids and t(eir derivatives

b) 6+36+=6+6+3(l) 8 +Sr($) → 6+36+6+Sr6+3(l) (1).

6+36+6+Sr6+3(l) 8 Na/+(a7) → 6+36+6+/+6+3(l) (1).

6+36+6+/+6+3(l) 8 / → 6+36+6/6+3 (l) (1).

4) I7uatio"s to describe the mecha"ism of additio" to 6=6 a"d 6=/ ( × )

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ropene !ith bromine "#N !ith propanone

'iilarities

%ddition reaction

Heterol)tic *ond *rea+ing

T,o&step process (an) 2

-ierences

/lectropilic reagent

%ttac+s electron&ric π *ond

nterediate is a positie ion (an) 2

cleopilic reagent

%ttac+s δ# end o polar C5O *ond

nterediate is a negatie ion (an) 2


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Answers to Topic - Review questions

1 Suta"e is "o"-polar. The o"l@

i"termolecular forces are ea Lo"do"

forces. 9t has the loest boili"$

temperature% 3

B (1).ropa"al has a polar 6=/ bo"d a"d so

there are attractio"s betee"

perma"e"t dipoles as ell as Lo"do"

forces. 9t boils at a hi$her temperature

tha" buta"e% 3

B (1).

+@dro$e" bo"di"$ is the stro"$est t@pe

of i"termolecular force. +@dro$e"

bo"di"$ is possible betee" the

molecules of etha"ol a"d betee" the

molecules of etha"oic acid (1).There is $reater scope for h@dro$e"

bo"di"$ i" etha"oic acid ith the −/+

$roup a"d / atom i" the carbox@lic acid

$roup. +e"ce both compou"ds boil at a

hi$her temperature tha" propa"al5 but

etha"oic acid boils at a hi$her

temperature (3H1

B) tha" etha"ol (31

B) (1).

2 a) ropa"o@l chloride5 6+36+6/6l (1)

b) Suta"-1-ol5 6+36+6+6+/+ (1)c) e"ta"-1-ol5 6+36+6+6+6+/+

(1); a"d sodium etha"oate

6+36//Na (1)

d) 6alcium etha"oate5 (6+36//)6a (1)

e) #eth@leth@l etha"oate5

6+36//6+(6+3) (1)

3 a) tep 1% +eat u"der rePux ith dilute

h@drochloric acid (1).

tep % :eact ith 6l* at room

temperature (1).b) 6+36+6+6/6l (1)5 buta"o@l

chloride (1)

c) Suta"amide (1)

(1)

4 a) ossible a"sers%

reactio" ith ma$"esium (1);

colourless Pammable $as $ive" o as

metal disappears (1); reactio" much

faster ith h@drochloric acid (1).

or

reactio" ith sodium carbo"atesolutio" (1); colourless $as $ive" o

hich tur"s limeater mil@ (1);

eervesce"ce much more vi$orous

ith h@drochloric acid (1).

b) 'cid solutio"s react i" a similar a@

because the@ co"tai" +8(a7) io"s

(1).

#$(s) 8 +8(a7) → #$8(a7) 8 +($)

(1)

6/3&

(s) 8 +8

(a7) → 6/($) 8+/(l) (1)

+6l(a7) is a stro"$ acid a"d so full@

io"ised (1); hile etha"oic acid is a

partiall@ io"ised ea acid (1).

The reactio"s ith +6l(a7) are much

faster because of the hi$her

co"ce"tratio" of h@dro$e" io"s (1).

5 a) 613+1/ (1).

b) The carbox@lic acid $roup ca" form

h@dro$e" bo"ds ith ater (1). Theh@drocarbo" part of the molecule is

"o"-polar a"d ca""ot easil@ brea

i"to the h@dro$e"-bo"ded structure

of ater (1). The lar$e h@drocarbo"

part of the molecule5 i"cludi"$ a

be">e"e ri"$5 mea"s that ibuprofe"

is o"l@ liel@ to be ver@ spari"$l@

soluble i" ater (1).

c) i) The same as the structure sho"

i" the 7uestio" but ith thecarbox@lic acid $roup tur"ed i"to

a sodium salt% −6//&Na8 (1).

ii) The same as the structure sho"

i" the 7uestio" but ith the

carbox@lic acid $roup tur"ed i"to

a" eth@l ester% −6//6+* (1).

+ a) The saturated fatt@ acid molecules

have a more re$ular shape (1); so

the@ pac to$ether more easil@ ith

a lar$e area i" co"tact for Lo"do"

forces (1). The double bo"d i" the

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u"saturated compou"d puts a i" i"

the molecules5 hich mea"s that

the@ do "ot pac so ell a"d melt at

a loer temperature (1).

b) ' solutio" of bromi"e (i" ater or

preferabl@ a" or$a"ic solve"t) (1);

tur"s from ora"$e to colourless (1);

he" shae" ith u"saturated cis-

octadec-H-e"oic acid (1); there is "o

cha"$e ith the saturated acid.

c) 9t is a" ester of propa"e-1553-triol

(1); ith three fatt@ acids (1).

d) i) +@dro$e" adds across the double

bo"d to form octadeca"oic acid

(1).

ii) 9" the cis compou"d the to

h@dro$e" atoms i" the −6+=6+−

are o" the same side of the double

bo"d ith both h@drocarbo"

chai"s o" the other side (1); i"

the trans compou"d the to

h@dro$e" atoms are o" opposite

sides of the molecule (1).

iii) uri"$ partial h@dro$e"atio" some of the cis u"saturated acids tur" to the

trans form (1). There is some evide"ce that trans acids raise the level of the

harmful form of cholesterol i" the blood; the form that ca" i"crease the ris of

heart disease. (1)

, a) ' co"de"satio" reactio" is o"e i" hich molecules Koi" to$ether b@ splitti"$ o a

small molecule5 such as ater5 from to fu"ctio"al $roups5 such as a carbox@lic

acid $roup a"d a" alcohol $roup (1); co"de"satio" pol@mers are produced b@ a

series of co"de"satio" reactio"s betee" the fu"ctio"al $roups of the mo"omers5

here each mo"omer has at least to of the reactive fu"ctio"al $roups (1).

b) ' molecule ith to carbox@lic acid $roups

(1)

' molecule ith to alcohol fu"ctio"al $roups.

(1)

c) ol@ester is used to mae !bres a"d fabrics for clothi"$ a"d other uses (1).

ol@esters ca" be melted a"d spu" i"to !bres hich are stro"$. The !bres i"

pol@ester fabrics do "ot stretch or shri" (1).

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Answers to Topic $ Review questions

1Type ofchromatography

$ethod ofseparation%adsorption or

relati&e solubility

'ample of anapplication

d&antages *imitations

H$C %dsorption (1 'td)ing te

eta*olis o

drgs in te*od)

(1

Can *e sed to

anal)se ionic salts

and also large*iological olecles

Can gie antitatie

as ,ell as alitatie

reslts (1

elatiel) epensie

Colns cannot *e too long

or te pressre needed toorce te liid trog

te is too ig and tis

can liit te degree o

separation acieed

(1

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:C /iter adsorption or

relatie sol*ilit);

depending on te

t)pe o coln (1

nestigation

arson;

detecting

polltants o

,ater; air and

ood

(1

n+no,ns cannot *e

identiied *ecase o te

lac+ o reerence data (1

2 a) i) Three e"viro"me"ts (1)

ii) Mrom the i"te$ratio" trace data% 3

% 3 % (1)

b) ea at δ = 1.0% : −6H3 (1); peas atδ = .1 a"d .*% co"siste"t ith

H36−6/− a"d :6H26/− (1).

c) ea at δ = 1.0% triplet to proto"s

o" a" adKace"t carbo" atom (1).

ea at δ = .*% 7uadruplet three

proto"s o" a" adKace"t carbo" atom

(1).

d) The compou"d is a carbo"@l

compou"d (1). 9t is a eto"e a"d "ot

a" aldeh@de (1). There is "o −/+$roup i" the molecule so it is "ot a"

alcohol or acid (1).

e) Suta"--o"e

(1)

3 a) e"ta"--o"e pe"ta"-3-

o"e

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Documents

Answer to Hodder Review Questions 1