1. C HEMICAL R EACTIONS Chapter 6 Section 2

2. R EACTANTS & P RODUCTS A Chemical reaction is the process by which atoms or groups of atoms in substances are reorganized into different substances. Can you give 4 examples of a chemical reaction?

3. A chemical equation shows that reactants, the starting substances, on the left side of the arrow and the products of the right side of the arrow Reactants  products Can you come up with a different model for reactants and products?

4. E NERGY OF R EACTIONS Activation energy  the minimum amount of energy needed for reactants to form products in a chemical reaction A candle will not burn until you light the wick. The flame provides the activation In every chemical reaction, there is a change in energy due to the marking and breaking of chemical bonds

5. E NZYMES A catalyst is a substance that lowers the activation energy needed to start a chemical reaction Special proteins called enzymes are the biological catalysts that speed up the rate of chemical reactions Can you give an example of enzymes?

6. L OCK & K EY The reactants that bind to the enzyme are called substrates The specific location where the substrate binds is called the active site.

7. F ACTORS THAT AFFECT ENZYMES pH Temperature Other substances

8. A CIDS & B ASES & B UFFERS Substances that release hydrogen ions when dissolved in water are called acids Substances that release hydroxide ions (OH-) when dissolved in water are called bases Buffers are mixtures that can react with acids or bases to keep the pH within a particular range.

9. pH = 7 is neutral pH = 7-14 is basic pH = 7-0 is acid Write down 2 examples of each in your notes! (neutral, basic, acid)