Heat is often used to bring about decomposition. As this is a very slow process, a catalyst is added. Catalysts that can be used include: zz
Manganese dioxide (a black powder). z z Catalase (found in liver, celery and almost every living cell).
Dropping funnel
Hydrogen peroxide Gas jar Oxygen Water Beehive shelf
12.5
z Manganese dioxide
Oxygen gas supports burning (combustion). A fire will not burn unless it has a supply of oxygen. A test for oxygen is that it will relight a glowing splint.
Comparing catalysts
Plan, design, carry out and write up an investigation to find out if manganese dioxide or catalase is a more effective catalyst for breaking down hydrogen peroxide into water and oxygen.
1. What factors will you change and what factors will you keep constant in this investigation?
2. How will you ensure this is a fair test? 3. How will you ensure that the gas you collect is oxygen? 4. What safety precautions will you need to take? 5. What will your results table look like? 6. What type of graph will you use to display your results? 7. How will you measure the effectiveness of the catalyst?
215 z Fig. 12.5.3
A test for oxygen is that it will relight a glowing splint
