1. Estimate the solubility of calcium carbonate at 25^oC in the presence of 0.09M CaCl₂(aq). [7]

2. Will BaSO₄ precipitate from a solution containing 1.5 x10^-4 M Ba⁺², barium ion, if enough soluble salt, Na₂SO₄, is added to make the solution 2.5 x10^-4 M in SO₄^-2? [7]

3. Describe oxidation reaction and use a rust of iron as an example. [5]

4. Describe the formation of a char coal. Motivate your answer with chemical reactions. [5]

5. List three possible disadvantages when a car owner replaces the manufacturers recommended gasoline with methanol. [3]