Keswick School
Chemistry Department
Summer A-level
preparation work
Exercise 1: Consolidating GCSE understanding
Fully re-familiarise yourself with the following topics from
GCSE which will be rapidly built upon during the first AS units:
From C1:
Metal extraction
Crude oil
Atomic structure
From C2:
Structure, bonding and properties
Moles and calculations
Reversible reactions
Redox reactions
From C3:
The Periodic Table
Energy changes
Titrations
Organic chemistry
Exercise 2: Memorising common formulae
You must memorise the formulae of the common ions shown
below and the formulae of the other common substances. It is
helpful to relate the charge on an ion to the position of the
element in the Periodic Table. You will be expected to know the
common ions throughout the course.
Positive ions:
Hydrogen
Lithium
Sodium
Potassium
Silver
Ammonium
Magnesium
Calcium
Barium
Iron (II)
Copper (II)
Zinc
Lead
HCl
Aluminium
HNO3
Iron (III)
H2SO4
+
H
Li+
Na+
K+
Ag+
NH4+
Mg2+
Ca2+
Ba2+
Fe2+
Cu2+
Zn2+
Pb2+
Negative ions:
Fluoride
FChloride ClBromide BrIodide
IHydroxide OHNitrate
NO3Oxide
O2Sulphide S2Sulphate SO42Carbonate CO32Common substances:
Hydrochloric acid
Al3+
Nitric acid
Fe3+
Sulphuric acid
Ammonia
NH3
Exercise 3: Determining formulae
Use the information from exercise 1 to deduce the formula of the substance given
below:
1. Silver bromide .....................
7. Ammonium sulphide........................
2. Sodium oxide.......................
8. Aluminium nitrate........................
3. Lead (II) oxide.............................
9. Ammonia.....................................
4. Iron (III) sulphide........................
10. Hydrochloric acid....................
5. Zinc carbonate............................
11. Sulfuric (VI) acid......................
6. Calcium hydroxide......................
12. Nitric acid................................
Exercise 4: Balancing equations
Symbol equations require balancing so that the stoichiometry is correct i.e. there
are the same number of each type of atom on both sides of the equation.
Balance the following equations:
S
1.
Li +
2.
SO2 +
O2 
SO3
3.
Na +
O2 
Na2O
4.
N2 +
H2 ⇌
NH3
5.
P+
Cl2 
PCl5
6.
Fe +
7.
C2H6 +
8.
NH3 +
H2O 
O2 
O2 
Li2S
Fe3O4 +
H2
CO2 +
H2O
NO +
H2O
Exercise 5: Forming symbol equations
At A-level, only symbol equations are used. Apply what you have covered in
exercises 2, 3 and 4 to form balanced symbol equations for each of the following:
1. Calcium hydroxide reacts with carbon dioxide to form calcium carbonate
and water
2. Titanium reacts with chlorine to form titanium chloride
3. Magnesium reacts with hydrochloric acid to form magnesium chloride and
hydrogen
4. Chorine reacts with potassium bromide solution to form potassium chloride
and bromine
5. Iron (II) oxide reacts with carbon monoxide to form iron and carbon dioxide
6. Carbon monoxide and nitrogen monoxide react to form carbon dioxide and
nitrogen
7. Ammonia and hydrochloric acid react to form ammonium chloride
8. Methane and steam react to form carbon monoxide and hydrogen
9. Sulphuric acid reacts with hydrogen bromide to form bromine, water and
sulphur dioxide
10.
Sulphur dioxide reacts with hydrogen iodide to form iodine, water and
hydrogen sulphide
Exercise 6: Presenting numbers
There are a number of considerations when presenting a numerical answer at Alevel. Convert the following as described:
Significant figures:
Represent the following numbers to the stated number of significant figures:
0.07894 (3 sig fig)......................
345789 (4 sig fig) .....................
6 (3 sig fig) .......................
8.174 (2 sig fig)………………..
7.994 (2 sig fig)
0.01 (4 sig fig) ........................
Decimal places:
Represent the following numbers to the stated number of decimal places:
78.544 (2 dp)..........................
0.00747 (2 dp)…………………
1.305 (2 dp).............................
6.44357 (3 dp)...................
3.071 (1 dp)……………….
4.45 (1 dp).........................
Standard form:
Represent the following numbers in standard form:
0.000167........................
0.1……………………….
0.0524............................
34500....................
98………………….
87000000......................
Decimal form:
Represent the following numbers in decimal form:
1.5 x 10-3 ......................
1 x 10-1..............................
4.6 x 10-2....................
5.34 x 104.......................
1x101………………..
1.3 x 105...........................
Converting units:
Convert the following quantities as described:
15g into kg.....................
5. 3.8kPa into Pa....................
15cm3 into dm3..................
6. 25oC into K..........................
25cm3 into m3....................
7. 260K into oC.......................
101300Pa into atm............
8. 3.3ml into cm3....................
Exercise 7: Practical work and risk assessing
As part of the practical element to your course, you must be able to research
practical techniques.
Before any practical work takes place, you will be expected to do some prepractical research and to familiarise yourself with what to expect and how to
ensure the safety of yourself and others.
The first two practical’s you will do next year are:
1. Making up a standard solution of potassium hydrogen phthalate(KHP)
2. Determining the concentration of sodium hydroxide by titrating with KHP
solution using phenolphthalein as an indicator
You should arrive in September with an idea of how to conduct these
investigations and a clear knowledge of risk assessing both.
Good luck and we look forward to seeing you in
September.