Practice  For the following reactions, write:  the word equation  the skeleton equation (unbalanced chemical equation)  the balanced equation 1. Potassium hydroxide and hydrogen are produced when potassium is placed in water. 2K + 2H 2 O  2KOH + H 2 2. The iron reacts with oxygen to produce rust, which is iron (III) oxide. 4Fe + 3O 2  2Fe 2 O 3

3. Zinc reacts with lead (IV) nitrate to produce zinc nitrate and lead. 2Zn + Pb(NO 3 ) 4  2Zn(NO 3 ) 2 + Pb 4. Calcium chloride reacts with silver nitrate to produce a white precipitate, silver chloride, and calcium nitrate. CaCl 2 + 2AgNO 3  2AgCl + Ca(NO 3 ) 2 5. Calcium carbonate decomposes into calcium oxide and carbon dioxide. CaCO 3  CaO + CO 2

6. Carbon monoxide and hydrogen gases are produced when carbon is placed in water. C + H 2 O  CO + H 2 7. In a hydrogen bomb, hydrogen gas and oxygen reacted to make water. 2H 2 + O 2  2H 2 O 8. Nitrogen monoxide from automobile exhaust reacts with oxygen to produce nitrogen dioxide, which is a toxic brown gas. 2NO + O 2  2NO 2

9. Hydrogen sulphide can be broken into hydrogen gas and sulphur. H 2 S  H 2 + S 10. Calcium metal and water combine to produce calcium hydroxide and hydrogen gas. Ca + 2H 2 O  Ca(OH) 2 + H 2