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1. What are differences between a physical and a chemical change? (lesson 34a)
2. What can you about the mass of a substance before and after a) a chemical change b) a physical change. (34a)
3. Complete the following equation:
   acid + base --> a ---- + -----. (34b)
4. Complete the following word equation:
   Sulphuric acid + copper oxide --> ------ -------- + ----- (34b)
5. Which gas is given off when a metal reacts with an acid? (34b)
6. What are the 3 main chemical elements in fertilisers? (34c)
7. Fertilisers can be made by reacting ammonia with an acid. What is this type of reaction called? (34c)
8. What is blast furnace used for? (34d)
9. Complete the following word equation:
   Calcium carbonate ^heat  > calcium oxide + ------ ------- (34d)
10. What do we call a reaction that gives out energy? (34f)
11. What happens to the temperature in an endothermic reaction. (34f)
12. What is another name for combustion? (34g)
13. Which gas is needed for fuels to burn? (34g)
14. What is the formula of carbon dioxide? (34g)
15. When iron oxide is turned into iron we say the iron oxide has been -------. (34g)

ANSWERS

1. Physical change - no new substances are formed. Chemical - new substances are formed.
2. a) The same b) the same.
3. Salt, water.
4. Copper sulphate, water.
5. Hydrogen.
6. Nitrogen, phosphorus, potassium.
7. Neutralisation.
8. To extract iron from iron ore.
9. Carbon dioxide.
10. Exothermic.
11. It decreases.
12. Burning (oxidation).
13. Oxygen.
14. CO₂.
15. Reduced.