Could somebody please help me balance these equations?

1. phosphorus (P4) + oxygen → diphosphorus pentoxide
2. potassium hydroxide → potassium oxide + water
3. aluminum + copper(II) nitrate → aluminum nitrate +
copper
4. pentane (C5H12) + oxygen → carbon dioxide + water
5. ammonium dichromate → chromium(III) oxide + nitrogen
+ water
6. barium chloride + sodium hydroxide → sodium
chloride + barium hydroxide
7. nickel chlorate → nickel chloride + oxygen
8. aluminum + hydrochloric acid → aluminum chloride +
hydrogen