1. (a) The diagrams below show the arrangement of atoms or molecules in five different substances A, B, C, D and E.

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1. (a) The diagrams below show the arrangement of atoms or molecules in five different substances A, B, C, D and E. Each of the circles, and represents an atom of a different element.

1 1. (a) The diagrams below show the arrangement of atoms or molecules in five different substances A, B, C, D and E. Each of the circles, and represents an atom of a different element. Give the letter of the diagram which represents: (i) a mixture of gases;... a single compound.... (b) The diagram below shows a model of a chemical reaction between two substances. (i) How can you tell from the diagram that a chemical reaction took place between substance P and substance Q? Shire Oak School 1

2 Substance P is carbon. Suggest what substances Q and R could be. substance Q... substance R... (iii) How does the diagram show that mass has been conserved in this reaction? maximum 5 marks 2. The drawing shows a gold mask from a tomb in Egypt. The gold is still shiny after thousands of years. (a) What is pure gold? Tick the correct box. a compound a mixture an element a solution Shire Oak School 2

3 (b) The list shows some of the properties of gold. It conducts electricity. It melts at 1064 C. It is yellow. It is easily scratched. It stays shiny. It conducts heat. (i) Which one of these properties shows that gold does not react with oxygen in the air? Which two of the properties above are properties of all metals? marks (c) Old iron objects from tombs in Britain are often covered with rust. Iron reacts with oxygen when it rusts. What else is needed for iron to go rusty? Choose one substance from the list below. lead nitrogen carbon dioxide water... (d) A box contains a collection of metal objects from a tomb. What piece of equipment would you use to separate the iron objects from the other metal objects?... Maximum 6 marks Shire Oak School 3

3. Some pupils carried out an investigation to find out whether more sugar or more salt dissolved in water at 60 C. Here are some of the steps in their investigation.

4 3. Some pupils carried out an investigation to find out whether more sugar or more salt dissolved in water at 60 C. Here are some of the steps in their investigation. They are not in the correct order. (a) Put the letters A, B, C, D and E in the boxes below to show the correct order of the steps in their investigation. 1st 2nd 3rd 4th 5th (b) Why did they use a measuring cylinder?... Shire Oak School 4

5 (c) They used water at 60 C in both beakers. What else did they do to make their investigation fair? (d) They counted the number of spatulas of sugar or salt added to the water until no more would dissolve. (i) Why was this not an accurate method of measuring how much sugar or salt they added? Suggest a more accurate method of measuring how much sugar or salt they added. (e) Jane predicted that more sugar than salt would dissolve. Complete the table to show a result which would support Jane s prediction. sugar salt number of spatulas 32 maximum 6 marks Shire Oak School 5

6 4. Alan put a test-tube containing solid stearic acid into a beaker of cold water. He heated the water until it boiled. to data-logger temperature sensor water solid stearic acid at the start electric hotplate He used a temperature sensor attached to a data-logger to record the temperature of the stearic acid over a period of 35 minutes. A graph of the results is shown below D 70 temperature of stearic 60 acid ( C) 50 A B C Stearic acid is a solid at room temperature. time (minutes) Shire Oak School 6

7 (a) (i) Which letter on the graph opposite shows the point at which the stearic acid began to change state?... Use the graph to find the temperature at which the stearic acid began to change state.... C (iii) Look at the graph. What was the physical state of the stearic acid: at point A?... at point D?... 2 marks (b) The test-tube transfers thermal energy from the water to the stearic acid. By what method is most of the thermal energy transferred? Tick the correct box. conduction evaporation convection radiation (c) Stearic acid boils at 360 C. The stearic acid could not boil in this experiment. Give the reason for this maximum 6 marks 5. Some crushed ice at -20 C was placed in a beaker. A thermometer was put into the ice, and the beaker was heated gently for 15 minutes. Shire Oak School 7

8 The graph shows how the reading on the thermometer changed over the 15 minutes temperature in ºC S R P Q time in minutes (a) By how much did the temperature in the beaker change during the 15 minutes?... C (b) Which letter on the graph shows: (i) when the ice is melting?... when the water is boiling?... Shire Oak School 8

9 (c) During the experiment, the beaker and its contents were quickly removed from the heat and weighed on a balance at the following times. at 0 minutes at 5 minutes at 10 minutes at 15 minutes (i) At which two times would you expect the readings on the balance to be the same?... minutes and... minutes Between which two of these times was the mass of the contents of the beaker changing most rapidly?... minutes and... minutes Maximum 5 marks 6. Diagrams A, B and C show three pieces of apparatus for separating substances. (a) Draw a line from each apparatus to the name of the method of separation. Draw only three lines. diagram of apparatus method of separation chromatography A distillation Shire Oak School 9

10 B filtration crystallisation (b) Debbie has a mixture of sand and salt water. Look at the diagrams in part (a). 3 marks (i) Which apparatus would Debbie use to separate the sand from the salt water? Give the correct letter.... Which apparatus would she use to separate pure water from the salt water? Give the correct letter.... Maximum 5 marks 7. Rema used the apparatus below to distil 100 cm 3 of water-soluble ink. Shire Oak School 10

11 apparatus A not to scale Shire Oak School 11

12 (a) Which processes occur during distillation? Tick the correct box. condensation then evaporation evaporation then condensation melting then boiling melting then evaporation (b) Give the name of the colourless liquid that collects in the test-tube.... (c) What would the temperature reading be on the thermometer when the ink has been boiling for two minutes?... C (d) (i) Water at 15 C enters the condenser at X. Predict the temperature of the water when it leaves the condenser at Y.... C Explain this change of temperature. Give two ways in which the water vapour changes as it passes down the glass tube in the condenser Shire Oak School 12

13 (e) Peter used the apparatus below to distil 100 cm 3 of water-soluble ink. apparatus B Why is the condenser in apparatus A better than the glass tube and beaker of water in apparatus B? not to scale maximum 7 marks Shire Oak School 13

14 8. Susie used chromatography to identify the coloured substances in the ink from a felt-tip pen. She used: green ink blue ink purple ink ink from her felt-tip pen. She used water as the solvent. red dark blue dark blue yellow water pink line where spots of ink were placed pale blue pale blue green ink blue ink purple ink ink from felt-tip pen Look at the diagram above. (a) (i) Which colours were present in the ink from the felt-tip pen?.. Shire Oak School 14

15 How many coloured substances were there in green ink? How can you tell?.... (iii) Susie placed the spots of ink on a line on the chromatography paper as shown in the diagram. To draw the line, Susie had to choose a felt-tip pen or a pencil. Which one should she use?... Give the reason for your answer..... (b) Susie used water as the solvent in this experiment. When she repeated the experiment with a different set of pens, it did not work. She then used ethanol instead of water. Suggest why the experiment worked with ethanol but not with water maximum 4 marks 9. At school Ellen heated some copper powder until it went black. (a) Give the name of the black substance formed when copper reacts with oxygen.... Shire Oak School 15

16 (b) Ellen added the black substance to some dilute sulphuric acid. The black substance reacted with sulphuric acid forming a blue solution of copper sulphate. What type of substance is copper sulphate? Tick the correct box. an acid a compound an element a mixture (c) (i) Ellen poured 20 cm 3 of the blue copper sulphate solution into a dish, A, as shown below. dish A copper sulphate solution She left the dish in a room at 21 C for two days. What two changes would Ellen observe in dish A two days later? marks Ellen poured 20 cm 3 of the same blue copper sulphate solution into another dish, B. She put a lid on dish B and left it in the room at 21 C for two days. lid dish B copper sulphate solution Shire Oak School 16

17 After two days the contents of dish B looked different from the contents of dish A. Give one difference Ellen would observe and explain how the lid caused this difference. 2 marks Maximum 6 marks 10. Gold, iron and magnesium are elements which conduct electricity. Sulphur and phosphorus are elements which do not conduct electricity. When iron and sulphur are heated together, they react to form a new substance called iron sulphide. (a) From the substances named above, give: (i) the name of a metal; the name of an element which is a non-metal; (iii) the name of an element which will rust; (iv) the name of a compound. Shire Oak School 17

18 (b) When magnesium and sulphur are heated together, they react. Write the name of the compound which is formed when magnesium reacts with sulphur.... Maximum 5 marks Shire Oak School 18

COMMON ENTRANCE STYLE EXAMINATION AT 13+ CHEMISTRY Practice Paper 2

COMMON ENTRANCE STYLE EXAMINATION AT 13+ CHEMISTRY Practice Paper 2 1. Underline the option which best completes each of the following: (a) A substance which only contains one sort of atom is magnesium