1 a) A gas which relights a glowing splint is
b) An example of a metal is
calcium iodine sulphur oxygen
c) An example of an element is
air limestone magnesium water
d) An example of a compound is
chlorine ethanol sodium sulphur
e) A substance which could be used to neutralise an acid could have a pH value of
2 5 7 10
f) A liquid which conducts electricity very well is
ethanol mercury sulphur water
g) When zinc is added to sulphuric acid the gas produced is
carbon dioxide hydrogen nitrogen oxygen
h) The pH value of lemon juice is about
3 7 10 14
(8)
2. Here is a list of oxides:
carbon dioxide copper oxide sulphur dioxide
hydrogen oxide magnesium oxide zinc oxide
From this list, select an oxide which best fits the following descriptions. (You may use each one once, more than once, or not at all.)
(a) A gas at room temperature (1)
(b) A liquid at room temperature (1)
(c) An acidic oxide (1)
(d) A basic oxide (1)
(e) Gives a milky suspension when passed through lime water (1)
(f) An atmospheric pollutant (1)
(g) An oxide which is white (1)
3. (a) The reaction of sodium hydroxide solution with hydrochloric acid is referred to as neutralisation.
(i) What are the products of this reaction?
and (2)
(ii) One of these products, when pure, is a solid. What process could be used to obtain a sample of this solid from the reaction mixture?
(1)
(b) The reaction between lead oxide and carbon involves both reduction and oxidation.
(i) What are the products of this reaction?
and (2)
(ii) Explain why this reaction is both reduction and oxidation.
(2)
(c) Copper carbonate decomposes when heated.
(i) What are the products of decomposition?
and (2)
(ii) What is meant by decomposition?
(2)
4. Explain what is happening in the following experiments.
(a) When carbon and copper oxide, both black, are mixed and heated in a test-tube, the mixture glows red hot and turns brown. When the hot mixture is tipped out onto a ceramic mat it turns black again.
(5)
(b) When a piece of iron is dropped into blue copper sulphate solution, the iron turns brown and the solution becomes less blue.
(4)
(c) When a piece of iron is left outside in the rain overnight, it turns rusty brown and its mass increases.
(2)
(d) When a small piece of magnesium ribbon is dropped into dilute hydrochloric acid, it fizzes and soon disappears.
(2)
5. (a) When a large amount of sugar is stirred into hot water, it forms a clear liquid called a syrup.
(i) Name the solvent (1)
(ii) Name the solute (1)
(iii) Suggest why we believe the formation of the syrup is a physical rather than a chemical change.
(2)
(b) (i) When sugar is heated, it forms a brown substance called caramel and steam is given off. On cooling, the caramel stays brown. Give two reasons why you think that this is a chemical change.
1. (1)
2. (1)
(ii) Draw a diagram of the apparatus you would use to heat some sugar and to condense the steam given off.
(4)
(iii) Describe a test you would do on the liquid you have collected to show that it was water.
Test: (1)
Result expected: (1)
6. Your school gardener tells you that wood ash is good for fruit trees. You decide to investigate some of the chemical properties of wood ash. You collect a sample of ash from the school bonfire heap and mix it up with distilled water.
(a) Describe what you would do next to obtain a solution from the mixture.
(1)
(b) How would you find out the pH of the solution?
(2)
(c) You find that the pH value of the solution is 11. What effect will the wood ash have on the soil under the fruit trees?
(1)
(d) Why is it important to collect a sample of wood ash for your experiments before it rains?
(2)
(e) When the solution in part (a) is evaporated to dryness it leaves a white solid. When dilute hydrochloric acid is added to this it fizzes. Describe what you would do next to investigate the gas given off and suggest what the results might tell you about the white solid.
(3)