Key Stage 3 Science Book 2 Assessments
Explaining Chemical Changes (Purple level)
1. Which of the following conditions cannot be treated by a neutralisation reaction? [1 mark]
a) Heartburn
b) Bee sting
c) Acid made by bacteria in the mouth
d) Sunburn
2. Which of the following statements is false? [1 mark]
a) All bases are alkalis
b) All alkalis are bases
c) An acid can neutralise a base
d) An acid can neutralise an alkali
3. Atoms of which two elements are always needed to make an alkali? [1 mark]
a) Calcium and oxygen
b) Hydrogen and aluminium
c) Sodium and hydrogen
d) Oxygen and hydrogen
4. Which of the following will neutralise stomach acid most quickly? [1 mark]
a) Milk of Magnesia (finely divided magnesium hydroxide suspended in water)
b) Calcium carbonate tablets
c) A solution of sodium hydrogen carbonate
d) Crushed calcium tablets mixed with water
5. Zinc reacts with sulfuric acid to produce a gas that burns with a ‘pop’. Which of the following
statements is false? [1 mark]
a) Hydrogen is produced
b) Zinc sulfate is produced
c) A salt is not produced
d) Water is not produced
© HarperCollinsPublishers 2014
Key Stage 3 Science Book 2 Assessments
6. When Battersea Power Station was built in the 1930s, it had scrubbers to remove sulfur dioxide.
Water was used to dissolve the gas and, in the presence of an iron oxide catalyst, it was converted into
sulfuric acid. However, the scrubbing process was discontinued in 1960. Which of the following was the
reason the process was stopped? [1 mark]
a) It was inefficient and sulfur dioxide still escaped into the atmosphere
b) It was too expensive
c) Sulfuric acid was discharged into the Thames causing harm to aquatic life
7. Which two of the following explain why alkali is usually found in toothpaste? [1 mark]
a) Bacteria produce acid in the mouth
b) It improves the cleaning power of toothpaste
c) It makes the toothpaste smoother and easier to squeeze from the tube
d) Too much acid in the mouth may cause tooth decay
8. Which two of the following describe what happens when magnesium burns in air? [1 mark]
a) The mass increases
b) The mass decreases
c) Magnesium oxide is formed
d) Carbon dioxide is formed
9. Name the substances which are not gases that form when calcium carbonate reacts with hydrochloric
acid. [2 marks]
10. Explain the difference between a base and an alkali. [2 marks]
11. You are given two large bottles. Each contains a colourless liquid – one liquid is an acid, the other is
an alkali. Describe how you could decide which is which without affecting all of the liquid in each bottle.
[2 marks]
© HarperCollinsPublishers 2014
Key Stage 3 Science Book 2 Assessments
12. Four indigestion tablets are tested by adding each to a beaker with acid in it.
Tablet brand
pH change
Time (minutes)
1 to 3
1 to 5
1 to 5
1 to 4
Which is the most powerful antacid brand and why? [2 marks]
13. Explain why the idea that all chemical reactions heat up the surroundings is a misconception. [2
14. Describe what happens when nitric acid is added to sodium hydroxide solution containing 2–3 drops
of litmus. Name the type of reaction that happened and the products of the reaction. [4 marks]
15. Look at the picture of the apparatus. It shows a burning candle floating on water inside a bell jar.
Explain how this apparatus could be used to give a rough idea of how much oxygen is in air. [4 marks]
© HarperCollinsPublishers 2014
Key Stage 3 Science Book 2 Assessments
16. James sets up an experiment using a glass tank and three candles. He makes some carbon dioxide
and points it into the other end of the tank. First the shortest candle goes out, then the middle one and
then the tallest one. What conclusions can he draw? [4 marks]
© HarperCollinsPublishers 2014