What is an oxidation reaction? Give an example of an oxidation reaction. Is oxidation an exothermic or an endothermic reaction?

Define a combination reaction. Give one example of a combination reaction which is also exothermic.

When water is added to a white powder 'A', vigorous reaction takes place and a large amount of heat is released. 'A' is also used for white washing. Identify 'A', write a chemical equation for its reaction with water and name the product.

What is meant by redox reaction? Identify the substance oxidised and reduced in the following reaction:

${\mathrm{Fe}}_2{\mathrm{O}}_3+2\mathrm{Al}\to {\mathrm{Al}}_2{\mathrm{O}}_3+2\mathrm{Fe}$

What is meant by redox reaction? Identify the substance oxidised and reduced in the following reaction:

$\mathrm{CuO}+{\mathrm{H}}_2\stackrel{\mathrm{heat}}{\to }\mathrm{Cu}+{\mathrm{H}}_2\mathrm{O}$

What information does the following equation convey? 

${\mathrm{CaCO}}_3 \to \mathrm{CaO} + {\mathrm{CO}}_2$.

Suggest two improvements by which the equation becomes more informative.

Identify the following chemical reaction: 

${\mathrm{ZnCO}}_3+2\mathrm{HCl}\to {\mathrm{ZnCl}}_2+{\mathrm{H}}_2{\mathrm{CO}}_3$