1. 6.2
Chemical Reactions

2. Chemical Reactions allow living things to grow, develop, reproduce, and adapt

3. Is this a chemical reaction?

4. What makes it a chemical reaction?
Atoms or groups of atoms in substances are reorganized into different substances.
Fe + O2 -> Fe2O3
Iron Oxide

7. Compounds Specific combination of elements in a fixed ratio.
H2O will always be made of H and O and in a 2:1 ratio
Chemically and Physically different than the elements that comprise them.
H2O is a liquid while H and O are gases
H2O has different chemical properties than H or O
They can not physically be broken down into elements. Have to have chemical means to break them down.

8. Compounds can only be chemically separated.
Process of chemically separating water= hydrolysis.

10. What are the products of the decomposition reaction?
Which molecule (O or H) will be attracted the cathode? Why?
Which molecule (O or H) will be attracted to the anode? Why?
Why does it appear that hydrogen is being produced at a faster rate?

11. Chemical Reactions What is needed for chemical reactions to start?
Energy
Activation energy= Minimum amount of energy needed from reactants to form products in chemical reactions

12. Endothermic -> Energy of products is higher than the energy of the reactants

13. Exothermic -> Energy of the products is lower than the reactants.

14. Endothermic and Exothermic
Endothermic Reactions
Exothermic Reactions
Photosynthesis
Water evaporation
Emergency Cold Packs
Burning a Candle
Combustion of fuels
Nuclear Fission
Cellular Respiration

15. How do living organisms get enough energy to allow all the chemical reactions to occur?

16. Enzymes Enzymes are biological catalyst
Catalyst lower the activation energy
A Catalyst doesn’t increase the amount of product or get used up in the reaction

17. Amylase Used to break down starch (complex) into sugar (simple).
Found in your saliva and helps aid in digestion.
Hold a saltine cracker in your mouth and see what happens!

18. Chicken Liver and Peroxide
Hydrogen peroxide (H2O2) is a harmful by- product that some of our cells give off.
The enzyme catalase (shown here in the chicken liver) breaks the H2O2 into H2O + O.
After the reaction is complete we can pour more peroxide onto the livers and the reaction will happen again because enzymes are not used up.

19. How enzymes work
The substrates (reactants) bind to the active sites on the enzyme.
Active site changes and the enzyme- substrate complex is formed.
Substrates (reactants) react to form products
Enzyme releases the product.

20. Important things to remember
Enzymes are not used up in a chemical reaction.
An enzyme’s name describes what it does.
The active site and substrates have complementary shapes. Think lock and key model
pH and temperature can affect enzymes

21. Use the diagram below to explain how lactase can break down the dairy sugar lactose.