Chemical Reactions and Equations

1
Chemical Reactions and Equations
2
Do Now

• Browning of an apple
• chemical reaction enzymes speed reaction
• 1. What are enzymes?
• 2. Which factors will affect the browning
  process and why?
• a. lemon juice
• b. boiling water
• c. sugar solution

3
Do Now

• Why is my fruit rusting? (turning brown)
• Iron
• containing
• compounds oxygen ---tyrosinase--gt Fruit
  rust

4
Chemical Reactions

• Chemical bonds are broken and reformed
  creating new substances
• Cellular respiration glucose and O2 reacting to
  form energy, CO2 and H2O
• C6H12O6 O2 -------gt CO2 H2O energy
• An iron chain rusting
• Fe O2 ----gt Fe2O3
• Reactants -----gt Products

5
Balanced Equations

• Law of Conservation of Mass matter cannot be
  created or destroyed, it just changes forms
• Number of atoms of each element on reactant side
  must equal the number of atoms on product side
• Coefficients Numbers in front of formula
  represent number of molecules of substance

6
Balanced Equations

• 4 Fe 3 O2 ----gt 2 Fe2O3
• C6H12O6 6O2 ----gt 6CO2 6H2O energy

Coefficients in red
7
Balanced Equations

• Try This
• CH4 O2 -----gt CO2 H2O
• CH4 2O2 -----gt CO2 2H2O

8

• Balance this
• H2O2 -----gt H2O O2
• 2H2O2 -----gt 2H2O O2

9
Energy of Reactions

• Activation Energy amount of energy necessary to
  start a chemical reaction
• In every chemical reaction there is a change in
  energy due to the breaking and making of bonds.

10
Exothermic Reaction
11
Exothermic Reaction

• Releases energy- usually in the form of heat
• Reactants have more energy than products
  (products more stable)
• Reaction more likely to go forward

12
Exothermic Reaction
Activation Energy
Amount of Energy released
Products
Reactants
13
Endothermic Reaction
14
Endothermic Reaction

• Absorbs energy
• Reactants have less energy than products
  (reactants more stable)
• Reaction less likely to go forward

15
Enzymes

• Reactions in living organism occur too slowly
• Need to speed up
• On the energy diagram what will enzymes affect?
• Activation Energy

16
Energy Diagram with Enzyme
17
Do Now

• Browning of an apple
• 1. Enzymes are proteins in living organisms
  that speed up reactions
• 2. a. lemon juice pH decreased
• b. boiling water temp. increased
• c. sugar solution solute
  concentration increased

18
(No Transcript)