1. Chemistry chapter 3 – Chemical quantities and calculations – balancing equation, Mr, Ar and gas changes
State the law of conservation of mass.
Calculate the Ar of: Mg Li F Cl H
Calculate the Mr of:
H2O O2
H2SO4
NaCl
MgO
Calculate the amount of water produced when copper sulphate crystals are heated. The starting mass of the copper sulphate crystals was 5.6g and it makes 2.4g of powder. How much water is produced?
Define the term uncertainty and state the calculation.
Define the terms:
Mean
Medium
Mode
Range
Anomaly
Balance these symbol equations:
Mg HCl  MgCl H2
CO H2  C8H H2O
Fe + H2SO4  Fe2(SO4)3 + H2
Describe what a limiting factor could be during a reaction.
State the 3 pieces of equipment we can use to measure the volume of gas released during a practical.
Define the terms:
Relative atomic mass:
Relative formula mass:
A reaction of 9g magnesium carbonate reacted with excess hydrochloric acid and stops after 5 minutes. The mass of the flask has reduced by 3.2g. Sketch a graph you would be likely to see below.
Calculate (Hint watch out for anomalies):
Mean for 5.6, 5.2, 5.4 and 5.9
Range for 9, 11, 20, 15 and 14
Calculate the percentage uncertainty for 8.9, 15.6, 8.4, 8.7 and 8.2
Describe why mass can appear to be lost during a reaction.

2. Chemistry chapter 3 – Chemical quantities and calculations – moles and concentration
HIGHER TIER: Define the term mole.
HIGHER TIER: Calculate the molar mass for 0.5 of a mole of:
CaCO3 N2
ZnO O2
NaCl
HIGHER TIER: Using the equation identified calculate:
Calculate the mass of hydrogen produced by the electrolysis of 6g of water. 2H2O  2H2 + O2.
What mass of aluminium is produced from 100g of aluminium oxide?
2Al2O3  4Al + 3O2
333g of calcium chloride (CaCl2) dissolves to form 120g of calcium and 213g of chlorine gas. Work out the balanced equation from the above masses.
Define the terms:
Concentration
Solute
Solvent
Solution
HIGHER TIER: Define Avogadro’s constant.
Draw a diagram to show a dilute and concentrated solution.
HIGHER TIER: Calculate the molar ass for 2 moles of:
CaCO3 N2
ZnO O2
NaCl
HIGHER TIER: Define the term molar mass.
Write the equation that links mass, concentration and volume together with the units.
1cm3 = ______________dm3
HIGHER TIER: Calculate the molar mass for 1 mole of:
CaCO3 N2
ZnO O2
NaCl
Moles questions middles: Concentration = 40g/dm3
1. 2H2O  2H2 + O2
H = 1, O =16
2H2O  2H2 + O2
36g 4g 32g
4/36 x 6 = 0.7g
2. 2Al2O3  4Al + 3O2
Al =27 , O = 16
2Al2O3  4Al + 3O2
204g 108g 96g
108/204 x 100 = 53g
3. CaCl2  Ca + Cl2
333/ / /71 =
= 3/3 3/ /3
= 1:1:1
CaCl2  Ca + Cl2
Calculate the concentration in g/dm3 of 20g dissolved in 0.5cm3? Show your working out.
HIGHER TIER: Write the equation linking, moles, mass of chemical and molar mass together with the units.