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ChemistryRevisionGuide

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Section A: Principles of Chemistry

1 a) electron b) electron

c) proton and neutron d) proton and electron

e) neutron

2 a) metals; non-metals; lost, gained; high; high

b) i) 2.8.2; 2.8.7 ii) 2.8; 2.8.8

3 a) Starting states B; B; A; C Finishing states A; C; C; A

b) B

c) element; mixture; mixture; compound

4 a) Atoms that have the same number of protons but different numbers of neutrons.

It is essential to include the word atom in your answer.

Alternative answer

Atoms with same atomic number but different mass numbers, or atoms of the same

element with different masses.

b) i) First row 37; 48 Second row 37; 87

ii)(85 ! 71) + (87 ! 28)

100= 85.6

c) They have the same electronic configuration.

Do not mention protons or neutrons in your answer.

Chemical reactions involve only electrons.

Alternative answer

Bothhave same number of electrons in the outer shell, or both have one electron inthe outer shell.

d) i) Rb2O; RbCl

ii) Any two from: rubidium fizzes or bubbles or moves around

rubidium disappears or dissolves

rubidium melts or forms a ball

rubidium catches fire or explodes or flame is produced

iii) 2Rb + 2H2O 2RbOH + H2

5 a) Electrons within the structure are free to move.

b) Ions cannot move until the lead(II) bromide is a liquid.

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c) First reaction B and reduction

Second reaction A and oxidation

d) i) Amount of Pb = 0.05 mol; Amount of Br2 = 0.05 mol

ii) Mass of bromine = 0.05 x 160 g = 80 g

6 a) i) (39 + 16 + 1) = 56

ii)14.0

56= 0.25 mol

iii) 0.25 !1000

250= 1.0 mol/dm

3

b) i)200

1000! 2.0 = 0.40 mol

ii)1

2! 0.40 = 0.20 mol

iii) 0.20 ! 24 = 4.8 dm3

7 a) Allotropy

Allotropy is no longer on the specification.

b) Covalent. The attraction of each of the two nuclei for a shared pair of electrons.

c) Cutting or drilling.

d)

e) Both are giant structures containing lots of covalent bonds that have to be broken.

It requires a lot of energy to break these bonds.

8 a) The force of attraction between two nuclei and a pair of electrons shared between them.

b) simple; weak; molecules; low.

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c) i)

ii)

9 a) A magnesium atom loses two electrons to form a magnesium ion.

A fluorine molecule/ two fluorine atoms gain two electrons to form two fluoride ions.

b) Magnesium; loss of electrons is oxidation.

c) i) Na+ and F

ii) NaF

d) Yellow

10 a) NaCl(s) and H2O(l)

b) i) Dilute nitric acid and aqueous silver nitrate.

ii) White precipitate.

iii) Diffusion.

c) i)

ii) (Simple) distillation.

11 a) (56 2) + (16 3) = 160

b) i)320 ! 1000

160= 2000

ii) 2 2000 = 4000

iii) 4000 56 = 224000 g = 224 kg

c) i) It restricts the capacity of the blood to carry oxygen.

ii) 5000

24 = 120000 dm

3

d) Fe2O3 + 3CO 2Fe + 3CO2

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e) i) Silicon dioxide (silica/sand)

ii) CaCO3 CaO and CaO + SiO2 CaSiO3

12 a) By heating.

b) i) Diffusion

ii) Ammonium chloride (NH4Cl)

iii) Ammonia particles move more quickly

iv) A red; B blue

13 a) Distillation

b) Evaporation

c) Filtration / decantation

d) Chromatography

e) Fractional distillation

14 a) i) (1 + 80) = 81

ii)1.62

81= 0.02

iii)0.02

250! 1000 = 0.08

iv) 0.08 x 81 = 6.48

b) i) HBr + NaOH NaBr + H2O OR H+ + OH H2O

ii) A proton is transferred from HBr to NaOH / OH

iii)20.0

1000! 0.20 = 0.004(00)

iv) 20.0 2 = 40.0 cm3

v) Methyl orange red to orange (allow yellow), OR

Phenolphthalein colourless to pink (allow red)

15 a) i) Giant lattice of positive ions with delocalised electrons.

ii) Can be beaten or hammered into shape.

iii) The layers of ions can slide over one another.

b) The two fluorine nuclei are attracted to a shared pair of electrons.

c) i) 2.7 ii) 2.8

d)

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16 a) i) Left-hand electrode ; right-hand electrode +

ii) H+; it is gaining electrons

iii) Horizontal line in right-hand tube halfway between the line given and the top of the tube.

The same number of moles of electrons produce twice as many moles of hydrogen as

oxygen.

b) i)0.40

2= 0.20

ii) (0.20 24) = 4.8 dm3

c) i)0.80

4= 0.20

ii) (0.20 32) = 6.4 g

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