1. Mr. Chapman Chemistry 30

2.  There are 3 major different things that we can change in a chemical reaction to increase its rate. Those 3 things are: Increase the temperature of the chemical reaction Increase the surface area of the reactants Increase the concentration of the reactants

3.  When we burned that gummy bear, we were able to greatly increase the rate of the chemical reaction by heating up the reactants (we melted the potassium chlorate, remember?) We miss you gummy, too bad you just had to go for the sake of science...

4. What’s the Problem? Why can’t we always do this?

5.  Changing the factors that affect the rate of a chemical reaction the most is not always practical.  For example, imagine the situation in your body. Your body breaks down glucose inside your body (the stuff the gummy was made out of) in the same way we watched it in class.  Your body needs to break down glucose quickly as well, so that it can get the energy it needs.

6.  However, your body needs to remain at the same temperature all the time in order for you to remain alive (this is known as homeostasis, which we will discuss in Biology 30). We can’t simply heat up your body in order to get the desired reaction rate.  So the question arises, what does your body to in order to break down sugar fast enough for you to use it?

7. Your body uses CATALYSTS to make the reaction happen faster, without an increase in temperature.

8.  Catalysts are substances that change the rate of a chemical reaction without being permanently altered themselves.  This is the definition of catalysts that I would like you to remember, and suggest that you write down: A CATALYST SPEEDS UP THE RATE OF A CHEMICAL REACTION, WITHOUT BEING CONSUMED BY THE REACTION.

9.  Catalysts that are in the human body are referred to as enzymes.  Enzymes function by

10.  A video of how catalysts work, by the CEBC: http://www.youtube.com/watch?v=9KQdF1bnXHE An example of a catalyzed reaction, and a brief explanation of catalysts: http://www.youtube.com/watch?v=mKLCRwBNOe4&f eature=related

11.  Watch this video of the creation of elephant toothpaste. The video is an example of the catalyzed decomposition of hydrogen peroxide into water and oxygen gas. http://www.youtube.com/watch?v=tnB-uU3w6g8