Variant 2 Feb/Mar 2016

1. Which pollutant gas can be produced as a result of incomplete combustion of octane, C₈H₁₈?

2. The elements in a group of the Periodic Table show the following trends.
1 The element with the lowest proton number has the lowest reactivity.
2 All the elements in the group form basic oxides.
3 The density of the elements increases down the group.
4 The melting point of the elements decreases down the group.
In which group are the elements found?

3. Which structure represents the sodium chloride lattice?

4. One method of preventing the rusting of iron is to keep oxygen away from the surface of the
metal.
Which way of rust prevention does not use this method?

5. The reaction below is called the ‘thermite reaction’.
2Al + Fe₂O₃ → 2Fe + Al₂O₃
Which pair of substances reacts in a similar way?

6. Brass is an alloy of two metals.
Which row gives a correct use for the two metals from which brass is made?

7. Why does a farmer put lime (calcium oxide) on the soil?

8. Magnesium nitride is formed when magnesium burns in air. Magnesium nitride is an ionic compound.
What is the formula of magnesium nitride?

9. Which row describes an endothermic reaction?

10. Which reaction does not occur in the extraction of aluminium?

11. In the Periodic Table, how does the metallic character of the elements vary from left to right across a period?

12. A salt is made by adding an excess of an insoluble metal oxide to an acid.
How is the excess metal oxide removed from the mixture?

13. Iron is extracted from hematite in the blast furnace.
The hematite contains silicon(IV) oxide (sand) as an impurity.
What reacts with this impurity to remove it?

14. Two gas jars are set up as shown.

The lid is removed and the gas jars are left to stand. After some time the contents of both gas jars are brown.
Which process causes this to happen?

15. Fertilisers are used to provide three elements needed to increase the yield of crops.
Which two compounds would provide all three of these elements?

16. What is a property of concentrated sulfuric acid but not of dilute sulfuric acid?

17. The statements below are about the alcohol homologous series.
The alcohols have the same ……1…… formula.
The alcohols have ……2…… chemical properties because they have the same ……3…… .
The melting points of the alcohols ……4…… as the number of carbon atoms increases.
Which words correctly complete gaps 1–4?

18. Which structure represents a compound that dissolves in water to form an acidic solution?

19. Nitrogen monoxide is produced in a car engine when petrol is burnt.
The gases from the car engine are passed through a catalytic converter.
In the catalytic converter the nitrogen monoxide reacts with carbon monoxide to form nitrogen and carbon dioxide.
Which statement is not correct?

20. Concentrated hydrochloric acid is a strong acid.

What is meant by the terms ‘strong’ and ‘acid’?

21. The partial structure of an addition polymer is shown.

What is the structure of the monomer used to make this polymer?

22. A sample of a green food colouring was separated into its component colours using paper chromatography.
The results obtained are shown.

What is the R_f value of the blue spot?

23. A reversible reaction is shown.

Which statement about an equilibrium mixture of NO₂ and N₂O₄ is correct?

24. The diagram shows how water is treated to make it suitable for drinking.

What happens in stage 2?

25. The electrolysis of concentrated hydrochloric acid is shown.

Which statement describes what happens to the electrons during the electrolysis?

26. Which molecule contains only single covalent bonds?

27. Zinc is extracted from zinc blende by roasting it in air to form zinc oxide.

The zinc oxide is then heated with carbon to form zinc.

The equations for the reactions are shown.

1 2ZnS + 3O₂ → 2ZnO + 2SO₂
2 ZnO + C → Zn + CO

Which statement about reactions 1 and 2 is not correct?

28. An element does not conduct electricity and exists as diatomic molecules.
Where in the Periodic Table is the element found?

29. Which piece of apparatus is used to measure variable quantities of liquid in a titration?

31. In which row are the substances correctly classified?

32. Which quantities of chemicals will react exactly with no reactants left over?

33. Which statement about polymers is correct?

34. Which substance could not be used as a fuel to heat water in a boiler?

35. The diagram shows an energy level diagram for a reaction.

The diagram shows that the reaction is ……1…… .

Increasing the temperature increases the rate of reaction. A reason for this is that the ……2……. .

Which words correctly complete gaps 1 and 2?

36. Which statement about catalysts in chemical reactions is not correct?

37. A substance is heated with aluminium foil in aqueous sodium hydroxide. A gas is produced which turns damp, red litmus paper blue.
Which anion is present in the substance?

38. X and Y are isotopes of the same element.
Which statement is correct?

39. Which compounds are alkanes?

40. Which oxide is amphoteric?