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Chemistry
Acids & Bases
Class Test
Duration – 45 minutes
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Adapted from materials copyright Scottish Qualifications Authority
Used with permission
National 5 Chemistry
Formulae & Reaction Quantities
1. A neutral solution contains
A
neither hydrogen ions nor hydroxide ions
B
equal numbers of hydrogen ions and hydroxide ions
C
more hydrogen ions than hydroxide ions
D
more hydroxide ions than hydrogen ions
Answer
1
2. The equation for the reaction is:
Pb2+(aq) + 2NO3-(aq) + 2Na+(aq) + 2I-(aq)

Pb2+(I-)2 (s) + 2Na+(aq) + 2NO3-(aq)
The spectator ions present in this reaction are
A
Na+(aq) and NO3-(aq)
B
Na+(aq) and I-(aq)
C
Pb2+(aq) and NO3-(aq)
D
Pb2+(aq) and I-(aq)
1
Answer
3. Which line in the table correctly describes what happens to a dilute solution of hydrochloric
acid when water is added to it?
pH
H+(aq)
concentration
A
increases
increases
B
increases
decreases
C
decreases
increases
D
decreases
decreases
1
Answer
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National 5 Chemistry
Formulae & Reaction Quantities
4. Part of a students experiment report is shown.
(a) Complete the instruction for step 4 of the procedure.
1
(b) Why is an excess of magnesium or magnesium carbonate added to the acid?
1
(c) The equation for the preparation of magnesium sulphate from magnesium carbonate is
shown.
MgCO3 (s) + H2SO4 (aq)  MgSO4 (aq) +
+
1
Complete the equation showing the formulae for the missing products.
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National 5 Chemistry
Formulae & Reaction Quantities
5.
A student carried out a titration to find the concentration of a potassium hydroxide solution
using 0∙10 mol l-1 nitric acid.
Equation
KOH(aq) + HNO3 (aq)  KNO3 (aq) + H2O(l)
(a) What must be added to the flask to show the end-point of the titration?
1
(b) The average volume of nitric acid needed to neutralise the potassium hydroxide solution
is 24∙6 cm3.
Calculate the concentration of the potassium hydroxide solution, in mol l-1.
3
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National 5 Chemistry
Formulae & Reaction Quantities
6. Ammonia gas NH3(g) and hydrogen chloride gas HCl(g), can both be dissolved in water to form
solutions.
If a bottle of each solution is placed next to each other in a fume cupboard and the stoppers
removed, both liquids evaporate and a white cloud is formed where the two gases meet.
Using your knowledge of chemistry, comment on the solutions formed and the product
formed when the gases meet.
3
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National 5 Chemistry
Formulae & Reaction Quantities
7. Some household cleaners contain the chemical limonene which gives them a lemon smell.
Using bromine solution, a student carried out titrations to determine the concentration of
limonene in a household cleaner.
(a) What average volume should be used in calculating the concentration of limonene?
1
(b) The equation for the reaction between limonene and bromine solution and bromine is
shown.
C10H16 (aq) + 2Br(aq)  C10H16Br4 (aq)
Calculate the concentration of limonene in the household cleaner.
3
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National 5 Chemistry
Formulae & Reaction Quantities
8. The main source of magnesium in Britain is sea water.
(a) The first stage in the production of magnesium is to remove the magnesium ions from
the sea water by reaction with calcium hydroxide solution.
Why can magnesium hydroxide and calcium chloride be separated by filtration?
(You may wish to use page 5 of the data book to help you)
1
(b) In the next stage magnesium hydroxide is reacted with hydrochloric acid.
Name the type of chemical reaction occurring in reactor 2.
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9. People often drink lemonade to quench their thirst.
Lemonade contains citric acid.
Suggest a pH value for lemonade.
1
[END OF QUESTION PAPER]
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