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A Level Chemistry Revision Guide
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Name : .....................................
AS Chemistry Start module 2015
Resource material booklet
This booklet contains much useful information.
[The majority of this information has been covered in theYear 10 and 11 courses]
The more of it you know the better your results will able. In Chemistry knowledge is the key.
If you are not good at remembering dont lose this booklet, keep it handy!
It will prove very useful throughout the year.
AS intro resource booklet 2015 page 1
Index.
page 3 General ideas on chemical formulapage 5 Table of ionspage 6 Writing ionic formulapage 8 Molecular formulae you need to know.page 9 Common names of chemical substancespage 11 Colours of chemical substancespage 13 The Bohr atompage 15 Electron configurationspage 21 Types bondpage 23 Structurepage 28 Types of chemical reactionpage 29 Salt dissolving
AS intro resource booklet 2015 page 2
Names and formulae of chemical compounds
There are millions of known chemical compounds.
These compounds have specific structures and are made up of simple particles, atoms, ions and molecules.
The name and formula give an idea of the composition and properties of a compound. So it is important to understand these names and formulae.
In Chemistry a compound often has a common name and a systematic name,
These compounds will also have a simple formula, but there can be other types of formula which can help to explain the properties of a particular compound.
Two examples are shown below to give you an idea of the importance of naming a substance, and writing the appropriate formula.
1. Compound 1
common name - common salt systematic name - sodium chloride emprical formula - NaCl
structural formula -
AS intro resource booklet 2015 page 3
2. Compound 2.
common name - glucose
systematic name - 2,3,4,5,6-pentahydroxyhexanal
emprical formula - CHO molecular formula - CHO
structural formula
glucose powder or CHOHCH(OH)CH(OH)CH(OH)CH(OH)CHO
or
Properties of these two substances
i. Both these compounds are white crystalline solids.ii. The melting point of salt is far higher than glucose.iii. Both are soluble in water.iv. A salt solution conducts an electric current, a glucose solution does not v. Sugar dissolves in alcohol, salt is insoluble in alcohol. vi. Sugar contains covalent bonds, salt contains ionic bonds
All these facts are due to the structure of these two substances.
AS intro resource booklet 2015 page 4
CationsCationsCations1+ ions 2+ ions 3+ ions
hydrogen Hlithium Lisodium Napotassium Ksilver Agcopper(I) Cuammonium NH
hydronium HOor hydroxonium
magnesium Mg2calcium Ca2iron(II) Fe2 pale greencopper(II) Cu2 bluezinc Zn2barium Ba2tin(II) Sn2lead(II) Pb2manganese(II) Mn2pale pinknickel Ni2 greencobalt(II) Co2pink
aluminium Alscandium Sciron(III) Fe yellow/brown
chromium(III) Cr green or blue
AnionsAnionsAnions1- ions 2- ions 3- ions
hydroxide OHhydrogencarbonate HCOhydrogensulfate HSOnitrate NOnitrite NOfluoride Fchloride Clbromide Briodide I
permanganate MnO purple
dihydrogenphosphate HPO
hypochlorite ClO or OClchlorate ClObromate BrOiodate IOethanoate CHCOOaluminate Al(OH) or AlO
oxide O2 various colours
carbonate CO2sulfate SO2
sulfite SO2
sulfide S2various colours
manganate MnO2 green
monohydrogenphosphate
HPO2
dichromate CrO2orange
chromate CrO2yellow
zincate Zn(OH)2 or ZnO2
nitride N
phosphide P
phosphate PO
AS intro resource booklet 2015 page 5
READ THE IDEAS ON THIS PAGE - THEN - WORK THROUGH QUESTIONS
Ionic substances are made from positive ions - cations negative ions - anions
These solids are made up and an ordered arrangements of these ions.These ordered structures are called crystals. Sometimes these are large and characteristic in shape other times the crystals are very small and appear as a powder.
These compounds have a neutral charge. The charges of the positive ions are countered by the charges of the negative ions.
An ionic formula represents the combination of these ions.
The symbol for the positive is written first followed by the symbol for the negative ion. The charges of the ions are omitted.
Thus copper oxide, a black insoluble solid, Cu O CuO( charges equal and opposite thus one ion of each required )
lead chloride, a white insoluble solid, Pb Cl PbCl( two Cl ions are needed to oppose the Pb ion the formulaof the solid show one Pb and two Cl ions )
aluminium sulphide, a white solid, Al S AlS( two Al ions, 6+, and three S ions, 6-, are needed to form a formula with neutral charge. )
iron(III) hydroxide, a red insoluble solid, Fe OH Fe(OH)( one Fe is required to oppose three OH ions.A bracket ( ) is put around the hydroxide ion because the ion comprises the atoms of oxygen and hydrogen and it needs three of each to balance )
2. Other examples to show you how to do this work
a) sodium nitrate, Na NO NaNOb) calcium sulphate, Ca SO CaSOc) ammonium carbonate, NH CO (NH)COd) aluminium oxide, Al O AlO
1
AS intro resource booklet 2015 page 6
3. Now try these, USE YOUR TABLE OF IONS and perhaps a scrap piece ofpaper to get the correct formula.
a.Zinc carbonate ................. b. Potassium fluoride .................
c. Magnesium sulphate ................. d. Copper oxide .................
e.Lead hydroxide ................. e. Sodium oxide .................
f. Aluminium chloride ................. g. Silver chloride .................
h. Potassium sulphide ................. i. Copper nitrate .................
j. Ammonium sulphate ................. k. Calcium iodide .................
l. Sodium phosphate ................. m. Iron (III) nitrate .................
n. Barium nitrate ................. o. Zinc nitride .................
p. Potassium chromate ................. q. Iron(II) sulphate .................
r. Calcium hydrogen carbonate .................
s. Aluminium sulphide .................
t. Magnesium ethanoate .................
u. Sodium zincate .................
v. Ammonium dichromate .................
w. Calcium dihydrogenphospate .................
x. Manganese (IV) oxide .................
2
AS intro resource booklet 2015 page 7
Molecular formulae
a) Molecular substances contain only non metal atoms. These are substances where the atoms are held together by covalent bonds.b) Sometimes the name gives a clue as to the formula. c) Other formulae need to be learnt. LEARN AS MANY AS POSSIBLE !!
Name Formula Properties1. Water HO a colourless liquid at room temp 2. Hydrogen peroxide HO a colourless liquid used as a bleach3. Carbon monoxide CO a colourless poisonous gas 4. Carbon dioxide CO a colourless gas turns limewater milky5. Methane CH natural gas used as a fuel gas 6. Ethane CH a gas found in LPG7. Ethene CH a gas used to make plastics 8. Ethyne CH a gas mixed with O to weld iron9. Sulphur dioxide SO a pollutant gas formed when sulfur burns 10. Ammonia NH3 strong smelling gas, used as a cleaner
11. Nitrogen dioxide NO brown pungent poisonous gas, air pollutant 12. Nitrogen N 80% of air
13. Hydrogen H explosive colourless gas, 96% of the universe
14. Oxygen O a colourless gas supports life & combustion
15. Ozone O a reactive poisonous form of oxygen
16. Chlorine Cl a yellow/green poisonous gas
17. Glucose CHO white solid, simplest of the sugars
18. Iodine I grey/silver solid, a mild antiseptic
19. Sulphur S yellow solid
20. Phosphorus P white unstable flammable solid
21. Hydrochloric acid HCl colourless liquid, stomach acid.22. Sulphuric acid HSO colourless liquid, battery acid.23. Nitric acid HNO colourless liquid.24. Ethanoic acid CHCOOH colourless liquid, found in vinegar.25. Carbon C a black solid, also formula for diamond, graphite or charcoal.
26. Glucose CHO white solid, the simplest of the sugars27. Ethanol CHCHOH a colourless liquid, alcohol
AS intro resource booklet 2015 page 8
Common names of substances in Chemistry
Alcohol ethanol CHCHOHAlum aluminium potassium sulphate 24-hydrate Al(SO).KSO.24HOAlumina aluminium oxide AlOBaking soda sodium hydrogen carbonate NaHCOBauxite ore containing aluminium oxide AlO ( FeO + SiO )Bleaching powder calcium chloride hypochlorite CaCl(OCl)Bluestone copper sulphate pentahydrate CuSO.5HOBrine sodium chloride solution/seawater NaClCarborundum silicon carbide SiCCaustic potash potassium hydroxide KOHCaustic soda sodium hydroxide NaOHChalk calcium carbonate CaCOCharcoal graphite, amorphous carbon CChile saltpeter sodium nitrate NaNOCommon salt sodium chloride NaClCryolite sodium aluminium fluoride NaAlFDiamond carbon CDry ice carbon dioxide solid COEpsom salts magnesium sulphate heptahydrate MgSO.7H0Ether diethyl ether CHCHOCHCHFlowers of sulphur sublimed sulphur SFools Gold iron sulphide FeSGlaubers salt sodium sulphate decahydrate NaSO.10HOGlycerin glycerol (from soap manufacture) CH(OH)CH(OH)CHOHGraphite crystalline carbon sheets CGypsum calcium sulphate dihydrate CaSO.2HOLaughing gas nitrous oxide NOLimewater calcium hydroxide solution Ca(OH)Litharge lead monoxide PbOMagnesia magnesium oxide MgOMagnetite triferric tetroxide, mixed iron oxide FeOMarble calcium carbonate CaCOMilk of magnesia magnesium hydroxide suspension Mg(OH)/HOMoth balls naphthalene CHNiter potassium nitrate KNONitroglycerine glyceryl trinitrate CH(NO)CH(NO)CHNOOil of vitriol sulphuric acid HSOPlaster of Paris calcium sulphate hemihydrate CaSO./HOQuartz silicon dioxide SiOQuicklime calcium oxide CaOQuicksilver mercury HgRed lead triplumbic tetroxide, mixed lead oxide PbORock salt sodium chloride NaClSal ammoniac ammonium chloride NHClSal volatile ammonium carbonate (NH)COSaltpeter potassium nitrate KNOSilica silicon dioxide SiOSlaked lime calcium hydroxide solid Ca(OH)Soda ash sodium carbonate NaCOSugar sucrose CHOTNT trinitrotoluene CH(NO)Washing soda sodium carbonate decahydrate NaCO.10HOWood alcohol methanol CHOH
AS intro resource booklet 2015 page 9
2 The following are of interest , but are not as important as those listed above.
Aqua fortis nitric acid HNOAqua regia nitric acid and hydrochloric acid HNO/HClBorax sodium tetraborate decahydrate NaBO.10HOBrimstone liquid sulphur SCinnabar mercury(II) sulphide HgSCorrosive sublimate mercury(II)chloride HgClCream of tartar potassium hydrogen tartrate KHCHODolomite calcium and magnesium carbonate CaCO.MgCOGreen vitriol ferrous sulphate heptahydrate FeSO.7HOHalite sodium chloride NaClHypo sodium thiosulphate pentahydrate NaSO.5HOLye sodium hydroxide NaOHMarsh gas methane CHMuriatic acid hydrochloric acid HClPrussic acid hydrocyanic acid HCNWhite vitriol zinc sulphate heptahydrate ZnSO.7HO
AS intro resource booklet 2015 page 10
Colours in ChemistryYear 11 level
SOLIDSSOLIDS1. White solids All Na, K compounds (except NaO, KO)
All Al, Mg , Ca , NH compounds (except some alums) (unless anion All Pb (except PbO, PbO, PbO, PbI, PbBr ) is coloured) All Zn (except hot ZnO)
All Ag (except AgBr cream, AgI pale yellow , AgO brown ) SiO pure sandP sometimes called yellowTiOCuSO anhydrous
2. White Precipitates Carbonates of Pb , Mg , Zn , Ca (Al(CO) does not exist)PbClPbSO, BaSO, CaSOHydroxides of Mg , Ca , Al, Pb , Zn , Sn
3. White precipitates Al, Zn , Pb , Sn in excess NaOH that dissolve AgCl, Zn(OH) in ammonia
all carbonates (any colour) in acidsall hydroxides (any colour) in acids
4. Yellow solids Sulphur, Au, AgI, FeS (iron pyrites)PbI, PbO, PbCrO and most CrO salts. ZnO when hot
5. Black solids Charcoal / graphiteCuO, CuS, PbSFeO, FeOMnO (or brown)
6. Brown solids PbO, AgOFeCl anhydrous is dark brown crystalsFeCl.6HO is yellow brown crystalsFeO is red brown, rusty
7. Red solids PbO , CuO, HgO , P, AgCrO
8. Grey solids CaC, FeS, I crystals ( vapour purple )
9. Orange solids (NH)CrO, KCrO, NaCrO
AS intro resource booklet 2015 page 11
10. Purple solids KMnO
11. Green solids CuCO, (really a basic carbonate, CuCO.Cu(OH) )Fe compounds (except FeO black, FeS yellow)Ni compoundsCrO
12. Blue solids CuSO.5HO, Cu(NO).3HOanhydrous CoCl
13. Pink crystals CoCl.6HOMn salts are very pale pink
14. Green precipitates CuCO.Cu(OH) from Cu + CO FeCO and Fe(OH) (both darken on standing in air)
15. Blue precipitates Cu(OH) dissolves in NH to dark blue solution Cu(NH)
16. Brown precipitates Fe(OH) , AgO from Ag + OH
LIQUIDSLIQUIDS17. Colourless Aqueous solutions of most soluble salts, acids and alkalis
HO, HO, Organic liquids, e.g. alkanes, alcohols, esters
18. Red Br
19. Coloured solut ions ( i) Green Fe , Ni , Cr, MnO ( ii) Blue Cu (sometimes green/blue) ( iii Purple MnO, I in non-polar organic solvents eg. hexane ( iv) Orange CrO (v) Brown Br solutions, I in polar solvents eg. propanone , I (I + I) (vi) Yellow Fe, CrO
GASESGASES
20.Colourless Most gases, Some fume in moist air e.g. HCl
21.Coloured Cl green/yellow F pale yellow NO brown
22.Coloured vapours [i.e. having B.Pts. above room temperature]Br orange/brown,I purple, Sulphur dark red
AS intro resource booklet 2015 page 12
nucleuscontains neutrons and protons
1234
electron shell, n
2 8 18 32
maximum number of electrons in shell, 2n
5
Bohr model of the atom
50
Atoms 1 - 20
Period 1
H H H He
Period 2
Li Be B C N flO F Ne
Period 3
Na Mg Al Si P
AS intro resource booklet 2015 page 13
Period 3
S fiCl Ar
Period 4 and then transition metals
K Ca fiSc
AS intro resource booklet 2015 page 14
Electron configurations of selected elements.
Noble Gases Group VIII or 0
98
818321882Rn
8181882!Xe
81882Kr
882Ar
82Ne
2He
72503218822n
helium gas in blimp excited neon atoms krypton filled bulb
AS intro resource booklet 2015 page 15
Electron configurations of selected elements.
Alkali Metals - Group I
all have 1 valence [outer] electron
98
1818321882Fr
18181882!!Cs
181882Rb
1882K
182Na
12Li
72503218822n
AS intro resource booklet 2015 page 16
Electron configurations of selected elements.
Halogens - Group VII
all have 7 valence [outer] electrons
98
78321882!At
7181882!I
71882!Br
782Cl
72F
72503218822n
chlorine gas bromine liquid iodine solid
AS intro resource booklet 2015 page 17
Electron configurations of selected elements.
First row of Transition metals Sc Zn
11882Cu
21682Ni
21382!Mn
11382Cr
21182V
21082Ti
2
28
98
31882Ga
21882Zn
21582Co
21482Fe
982Sc
82Ca
72503218822n
Scandium metal Vanadium metal Manganese metal
AS intro resource booklet 2015 page 18
Other elements
2
29
118
118
118
98
11832321882Rg
825321882!Am
21321882U
32882Au
1882Ag
82Cu
72503218822n
Biggest known nugget Americium-241 cubes of Uraniumof Gold in a smoke alarm
AS intro resource booklet 2015 page 19
The only atoms that can exist on there own at room temperature are the Noble Gases.
These exist as monatomic gases at room temperature.
At room temperature all other atoms have to form links or bonds with each other.
Four types of chemical bond
1. Ionic bond - between cation, +ve and anion, -ve
2. Covalent bond - between non metal atoms,[ sigma and pi , non-polar, polar, strongly polar & coordinate bonds ]
3. Metallic bond - between metals, metal cations and their valence electrons
4. Intermolecular - between molecules or atoms of Noble Gasesbond [ H - bonds, permanent dipoles, temporary or induced dipoles ]
[ Understand and identify these in a substance and you will begin
to make sense of this subject. ] ! !
AS intro resource booklet 2015 page 20
Cl Cle
e
a non-polar bond
a pair of electrons shared between two non-metal atoms with the same electronegativity ens Cl = 3.0
HCle
e
a polar bond
a pair of electrons sharedunequally between two non-metal atoms with different electronegativitiesens Cl = 3.0, H = 2.1
HOe
e
a strongly polar bond
a pair of electrons sharedunequally between two non-metal atoms with very different electronegativities, O-H, N-H, F-Hens O = 3.5, H = 2.1
Cl Na an ionic bond
a pair of electrons not sharedbetween anon-metal and a metalens Cl = 3.0, Na = 0.9
NaeNa a metallic bond
an attraction between metal cationsand their mobile valence electronsens Na = 0.9
types of bond
AS intro resource booklet 2015 page 21
Structure
Types of structure that you should be familar with
i.e. you should know about
a. particles holding structure together
b. types of force holding particles together
c. the relative strengths of these forces
d. the physical properties involved with these structures.
AS intro resource booklet 2015 page 22
TYPES OF SOLIDS
Forces of Attraction in Crystall ine Solids Crystalline solids have an ordered array of atoms or molecules. This array is called a lattice. The atoms or molecules in solids are held together in four different ways and these are: Molecular Solids: Molecules are held together by relatively weak forces (van der Waals, hydrogen bonding) so molecular solids have low melting points and in many cases only form solids at low temperatures. e.g. ice, solid CO. Most of the non-metal elements e.g. chlorine and neon, form solids of this type. The forces between the molecules are weak BUT within the molecule e.g. CO there are strong forces holding the atoms together.
AS intro resource booklet 2015 page 23
Ionic Solids: The lattice is made up of positive and negative ions. The force of attraction between the oppositely charged ions is strong compared to molecular solids. They have high melting points. Each ion is surrounded by neighbours of opposite charge and there are no separate molecules. Ions are not easily moved from their lattice sites, so typical ionic solids are hard and rigid, though brittle [If an ion is displaced, it moves closer to an ion of like charge which repels it, thus breaking the lattice]. They shatter easily and cannot be shaped by hammering and bending. The electrons are localized on the ions and ionic solids only conduct electricity when they are molten and the ions are free to move. Examples are NaCl [sodium chloride] and KI [potassium iodide].
Network Covalent Solids: Atoms are covalently bonded throughout the entire solid, thus the force of attraction is a covalent bond. The strong attractive force gives them very high melting points. The electrons are localized and are not free to move making them insulators. Examples are diamond, quartz (SiO2) and the silicate minerals. In diamond each carbon atom is bonded tetrahedrally to four other carbon atoms. Quartz has a lattice of SiO4 tetrahedra where every oxygen is bonded to two silicon atoms. The other two allotropes of carbon (different forms of the same element in the same physical state) are also network solids and are graphite and the fullerenes. Both conduct heat and electricity as the electrons can move freely through the solid. Graphite consists of sheets which can move over each other due to weak forces holding the sheets together. The fullerenes consist of balls of between 30 - 72 Carbon atoms.
diamond graphite
AS intro resource booklet 2015 page 24
Metall ic Solids: The metal atoms occupy regular lattice sites, however the valence electrons can move throughout the entire solid. These delocalized electrons readily carry heat and electricity throughout the solid. The mobile electrons produce the typical sheen or metallic lustre characteristic of metals. Since the force of attraction is not localised, the metal atoms can slide from one lattice site to another, making metals malleable (shaped by hammering) and ductile (drawn into wire). The strength of the metallic bond is quite variable as indicated by the range of melting points from tungsten, 3422 0C to mercury, !39 0C.
AS intro resource booklet 2015 page 25
This table summarises some of the facts about the four types of solids.
TYPE of SOLID
METALLIC
IONIC
MOLECULAR
COVALENT
Entity
atoms
ions
molecules
atoms/molecules
Force of Attraction
metallic
bond
ionic bond
Van der Waals
covalent bond
Strength of the Force of
Attraction
variable
strong
weak
strong
Texture
soft
hard / brittle
soft
very hard
Conductor of
Heat or Electricity
conductors
insulators [conduct
when molten]
insulators
insulators
(except graphite)
Melting Point
variable mp
-39 to 4000C
high mp 600 to 3000C
low mp
-272 to 400C
very high mp
1200 to 4000C
Solubility
insoluble in
water/organic
soluble in
water
soluble in organic solvents
insoluble
Examples
Fe Pb Sn
NaCl MgO
Na2SO4
sugar CH4 CO2
diamond graphite quartz
Amorphous Solids An amorphous solid is not crystall ine as the atoms or molecules are not arranged in a regular lattice and is formed when the shape of the molecule is too complex, the molecules are frozen too rapidly or when impuriites prevent a regular lattice. They include glass, rubber and plastics. Amorphous solids can be considered to be supercooled liquids of high viscosity.
AS intro resource booklet 2015 page 26
Types of chemical reaction
1. Combustion A reaction where a substance burns, normally in oxygen, to produce energy in the form heat, light and sometimes sound.
Example : calcium + oxygen calcium oxide
2. Exothermic A reaction where energy is released, in the form of heat or light or sound. The enthalpy [stored energy] of the products is less than that of the reactants.
Example : any combustion reaction, most spontaneous reactions.
3. Endothermic A reaction where energy is absorbed. Normally the reaction mixture gets cooler. Its enthalpy increases.
Example : ammonium salts dissolving.
4. Dehydration A reaction where a substance loses water to form a new substance. [it is not dried]
Example : sucrose with conc sulfuric acid carbon + water 5. Hydrolysis A reaction with water to form a new compound. [not dissolving something in water]
Example : sulfur dioxide + water sulfurous acid
6. Displacement A reaction where a reactive element displaces a less reactive element Example : zinc + copper sulphate copper + zinc sulphate
7. Effervescence A reaction where bubbles of gas are vigorously produced.
Example : acid + metal salt + hydrogen
8. Decomposition A reaction where a substance breaks down into simpler substances. Can be achieved by heat, a catalyst and by electrolysis.
A B + C
Example : magnesium hydroxide magnesium oxide + water
AS intro resource booklet 2015 page 27
9. Precipitation A reaction where two solutions are mixed together to produce a suspension which contains an insoluble product known as a precipitate.
Example : sodium chloride + silver nitrate sodium nitrate + silver chloride
a white ppt.
Solubility of ionic solids
------------all common ones
------------all common ones
------------all common ones
Pb,Ba, Ca and (Ag)the rest
the rest Ag,Pb also Cu
the restNa,K,Ba react with
water
the restNa,K, NH,
Ca and Ba slightly
the restNa,K and NH
insolublesoluble
CHCOO
NO
HCO
SO
Cl, Br, I
O
OH
CO
10. Combination A reaction where two or more substances combine to form a more complicated product. D + E F
Example : magnesium + nitrogen magnesium nitride
11. Neutralisation A reaction where an acid reacts with a base to form a salt and water (and CO when the base is a carbonate or hydrogencarbonate)
Example : nitric acid + lead(II) oxide lead nitrate + water
AS intro resource booklet 2015 page 28
What happens when salt dissolves? Why does it disappear? Why is it soluble?
AS intro resource booklet 2015 page 29