1. CuSO4   calcium carbonate   sodium carbonate   copper sulfate   potassium hydroxide   Hint Hint       2. H2O   water   potassium nitrate   hydrogen peroxide   calcium sulfate   Hint       3. KMnO4   ammonia   carbon dioxide   potassium permanganate   calcium sulfate   Hint       4. CO2   hydrochloric acid   carbon dioxide   potassium nitrate   water   Hint       5. H2O2   hydrogen peroxide   sodium hydroxide   sodium carbonate   carbon dioxide   Hint       6. NH3   copper sulfate   carbon dioxide   ammonia   potassium nitrate   Hint       7. NaOH   sodium hydroxide   copper sulfate   sulfuric acid   sodium carbonate   Hint