WHY|REASONING CHEMISTRY?
AIR, COMBUSTION, RUSTING AND FIRE FIGHTING
1. Extinguishing a fire caused by burning kerosene, carbon dioxide is used in preference to water. Explain why?
2. Give a reason why, carbon dioxide is used as a fire extinguisher?
3. Carbon dioxide is not used as a fire extinguisher in class D fires. Explain why?
4. Burning magnesium continue to
burn inside the gas jar full of carbon dioxide. Explain why?
5. A piece of burning magnesium continues to burn in a gas jar of Sulphur dioxide gas. Explain why?
6. A small child has been playing with matches and its clothes have caught fire. Explain how you would put out the flames.
7. Zinc is used to cover iron so as to prevent rusting of iron. Explain
why?
8. Explain why motor vehicles based in Mombasa rust much faster than those based in Nairobi?
9. If the tin surface is scratched then the iron will rust. Why does this not happen with zinc plating
(galvanizing)?
10.Aluminium metal would protect iron from rusting better than zinc metal. Explain why?
11.It is not advisable to wash vehicles using sea water. Explain why?
12.Why do car exhaust rust faster than other structures made of steel?
13.The parts of shipwrecks made of iron rust more slowly in deep water. Explain why?
14.Alkaline medium inhibits the rusting of iron. Explain why?
15.Iron does not rust even if zinc coating is broken in a galvanized iron pipe. Explain why?
16.Zinc is used to coat for iron and not vice versa. Explain why?