CAMP DAVID ACADEMY EXAM
CHEMISTRY
Paper 4 Theory (Extended)
Form 5
9701/22
December 2022
1hour 45 minutes
Instructions to candidates:
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Answer All Questions
The total marks of this paper is 50
You may use your calculator
Crying is Allowed but do it Silently without disturbing others.
1. Define the following terms:
(i) Relative isotopic mass [2]
(ii) Relative atomic mass [2]
(iii)Spectator ion [2]
2. Radium consists of 25 isotopes, of which two of them are naturally occurring isotopes
namely, 224Ra, and 226Ra, in the atomic ratio of 3:5. Calculate the relative atomic mass
of Radium to 3sf. [3]
3. Write an ionic equation for the reaction between sodium sulphate and calcium. [2]
4. Nitrogen exhibits a range of oxidation numbers in its compounds.
a) Complete the table below which refers to possible reduction products of nitric acid.
Formula of products
NO2
N2O
NH2OH
NH4+
Oxidation of nitrogen
[4]
b) Copper can reduce nitric acid to NO2. Write a balanced equation for this reaction.
[3]
c) Aluminium can reduce nitric acid to NH4+. Write a balanced equation for this
reaction. [3]
d) Suggest a reason why the reduction products of nitric acid are different for each of
these two metals. [3]
e) The compound of NH2OH is oxidised by Fe3+ (aq), which is itself reduced to Fe2+
(aq). In an experiment, 25.0cm3 of 0.100 mol/dm3 NH2OH required 25.0 cm3 of
0.200 mol/dm3 Fe3+ for complete reaction.
i. How many moles of Fe3+ react with one mole of NH2OH? [3]
ii. What changes in oxidation number does the nitrogen in NH2OH undergo?
[1]
iii. Which formula from the table in (a) corresponds to the nitrogen containing
product of this reaction? [1]
iv.
Construct an equation for the reaction of NH2OH with Fe3+. [3]
f) Write balanced equations for the complete combustion of H2S and of CS2. [6]
5. Write a Dot and Cross diagrams for the following elements
i.
MgCl2. [3]
ii. CO. [3]
6. King George adds excess large pierces of magnesium carbonate, to dilute
hydrochloric acid, and measures the volume of carbon dioxide gas given off.
i.
Write a balanced equation for the reaction between MgCO3 and HCl. [3]
ii.
Determine the volume of carbon dioxide given off when excess magnesium
carbonate is added to 35.0 cm3 of 0.200mol/dm3 hydrochloric acid at rtp and
pressure. [4]
The rule of every examination shall still apply: EACH MEN FOR HIMSELF GOD FOR
US ALL!!!