1. Enzymes

2. Lesson Starter
With the person next to you, try and think of as many CHEMICAL REACTIONS as you can.. (write these down in a spider diagram in your jotter)

3. Common Chemical Reactions
Photosynthesis
Fireworks
Digestion
Common Chemical Reactions
Baking a cake
Starting a car
Striking a match

4. What is a chemical reaction?

5. What is a chemical reaction?
A process in which one or more substance (reactants) is chemically changed into one or more new substance (product)
Reactants
Product

6. Chemical Reactions
The speed that a reaction occurs at is called the REACTION RATE
Most chemical reactions occur very slowly at normal temperatures
We can increase the speed of a chemical reaction

7. Increasing reaction rate
Increasing temperature
Increasing concentration of a reactant
Breaking down solids into smaller pieces
USING A CATALYST

8. Investigating Catalysts
Hydrogen peroxide (H2O2) is a harmful liquid which (under normal conditions) will very slowly break down into water (H2O) and oxygen

9. Experiment: AIM We are going to carry out an experiment which will:
Investigate the effect of using a catalyst on the decomposition rate of hydrogen peroxide

10. Method Set up two test tubes in a test tube rack
Small quantity of manganese dioxide
Set up two test tubes in a test tube rack
Into both test tubes pour in some hydrogen peroxide
Into one of tubes add a small quantity of manganese dioxide
The other test tube will be a CONTROL
Hydrogen peroxide

11. The importance of a control
A control is a copy of the experiment in which all factors are kept exactly the same except for the one being investigated in the original experiment – In this case the use of the catalyst
When 2 results are being compared, any difference found between the two must be due to that one factor.

12. Method Set up two test tubes in a test tube rack
Small quantity of manganese dioxide
Set up two test tubes in a test tube rack
Into both test tubes pour in some hydrogen peroxide
Into one of tubes add a small quantity of manganese dioxide
The other test tube will be a CONTROL
Note down your observations in your book
Test the gas given off using a GLOWING splint
Hydrogen peroxide

13. Observations

14. Oxygen was present as the glowing splint relit
Conclusion
The tube with manganese dioxide added produced bubbles
Adding the manganese dioxide increased the rate at which bubbles were produced
Oxygen was present as the glowing splint relit

15. What are Catalysts
Substance which INCREASES the rate of a chemical reaction
They are NOT CHANGED or USED UP in the reaction (reusable)
They LOWER the energy needed to kick start the reaction

16. Uses of catalysts
Modern cars have a catalytic converter to help reduce the production of toxic gases.
Catalytic converters use a platinum and rhodium catalyst
Increases the speed that (harmful) carbon monoxide and unburnt fuel (from the exhaust) reacts with oxygen from the air- help protect the environment
The catalysts are designed to work best at the high temperatures found in the engine.

17. Task: Write a report Aim of the experiment
Method- A step by step guide to what you did (including control and why). Include diagrams
Results- what did you see happening in both test tubes?
Conclusion- why did you see what you did? What did the manganese do? What is manganese?
Information about catalysts- what is a catalyst? Why is it useful? Where are catalysts used in every day life?