Transcript Chemical Reactions
Chemical Reactions
Chemical Reactions and Enzymes
• What does a chemical formula symbols, states, Draw and label a chemical formula: CO 2 + H 2 O
H 2 CO 3 Reactants Products
Chemical Reactions and Enzymes
chemical reaction:
process that changes one set of compounds ( reactants ) into another set of compounds ( products ) A.
example
: wood + oxygen carbon dioxide + water + energy Reactants Products
B.
example
:
How many molecules are in a chemical formula/equation? Photosynthesis: Put a box around the products and circle reactants carbon dioxide + water
glucose + oxygen Reactants Products
chemical equation:
CO 2 + H 2 O Reactants
C 6 H 12 O 6 + O 2 Products
C. Conservation of matter: During a chemical reaction, atoms are not created or destroyed – just rearranged . Therefore, chemical equations must be balanced so there is the same number of atoms on both sides of the equation.
6 CO 2 2 + H 2 O 2
C 6 H 6 12 O 12 6 6 + O 6 2 O 2
•
Using the Equation for Wood Burning: Answer the questions
Write this equation down!
C 6 H 12 O 6 + 6 O 2
6 CO 2 + 6 H 2 O
C 6 H 12 O 6 + 6 O 2
6 CO 2 + 6 H 2 O
C 1)How many molecules are on the:
• Reactants side • • • 7 Products Side • 12 What are the names of the molecules: • Glucose and Oxygen • Carbon Dioxide and water
C 6 H 12 O 6 + 6 O 2
6 CO 2 + 6 H 2 O
C. 2) How many atoms are on the:
Reactants side: • • • 6 C, 18 O, 12 H Total = 36 Products Side: • • 6 C, 18 O, 12 H Total = 36 This demonstrates the conservation of Matter !
C 6 H 12 O 6 + 6 O 2
6 CO 2 + 6 H 2 O
C. 3) How many elements are on the:
• • • Reactant Side: • 3 Product Side: • 3 What are the elements?
• Carbon • Hydrogen • Oxygen
Apply what you’ve LEARNED • • 4.) 2 H • 2 O 2
2H 2 O + O 2 # of reactant molecules: 2 # of product molecules: 3 a.) What are the molecules: • • • Hydrogen Peroxide Water Oxygen
Apply what you’ve LEARNED 5.) 2 H • 2 O 2
2H 2 O + O 2 # of reactant atoms: 8 • (4 H and 4 O) • # of product atoms: 8 • (4H, 2O, 2O)
Apply what you’ve LEARNED • • 6.) 2 H • 2 O 2
2H 2 O + O 2 # of reactant elements: 2 # of product elements: 2 What are the elements: • • Hydrogen Oxygen
II. Speed of Reactions
• The speed of a reaction depends on whether is absorbs or releases energy.
Chemical reactions that Release energy….
• Often Occur Spontaneously (without warning) • Example: Explosion gun powder or fireworks
Chemical reactions that Absorb energy….
• Will not occur without a source of energy. • Example: Instant Ice Packs or Photosynthesis.
Chemical Reactions and Enzymes III. Label the graph: Products Activation Energy Reactants Energy Absorbing Activation energy Reactants Products Energy Releasing
A. All reactions require some energy to start:
activation energy.
Example: if some reactions that release energy did not require activation energy, what could happen to the pages of your text book as you sit here reading? They could spontaneously combust into flames.
B. catalyst
: substance that speeds up a chemical reaction by lowering the activation energy
Catalysts found in living things are called
enzymes
C. Enzymes
•provide a
site where the reactants of a chemical reaction can be brought together
•are not
used up or changed during the chemical reaction
•
active site:
part of the enzyme where the reactants bind (stick) •
reactants:
molecules at beginning of a chemical reaction. Called the
substrate
when they encounter an enzyme.
•
substrate
only fits into the active site of the correct enzyme (like a key and lock )
Labeled diagram:
Enzyme Active Site Reactants
III. How does an enzyme work?
A. substrate binds to the enzyme
Enzyme Substrate Active Site Reactants
III. How does an enzyme work?
A. substrate binds to the enzyme
Enzyme Substrate Active Site
III. How does an enzyme work?
B. reactants converted to product
Enzyme Product Active Site
III. How does an enzyme work?
C. products are released – enzyme is free to bind new substrate
Enzyme Product Active Site
IV. Enzymes only work in specific conditions A. temperature: heat=destroy enzyme, cold= slow enzyme down B. pH: changes the shape of the enzyme and its active site C. coenzymes: make enzymes work better D. inhibitor molecules: block substrate from entering active site
Balancing Chemical Equations
• • A balanced equation shows that every atom of the reactant becomes part of the product .
Atoms are never lost or gained.
• Balancing an equation may require a coefficient , which is then given to each atom in the formula.
Steps to Balancing an Equation 1. Count the atoms of each element in the reactants and in the products.
H=2 H 2 + O 2 O=2
H 2 O H=2 O=1
2. Place a coefficient next to each formula that needs to be increased and recount the atoms H 2 H=2 + O 2 O=2
H=4 2 H 2 O O=2
3. Continue to add coefficients until the number of atoms is the same on both sides of the equation.
2 H 2 H=4 + O 2 O=2
H=4 2H 2 O O=2
pH Change or boiling:
Enzyme Product
No Product Made
Active Site
Inhibitor Molecules:
Enzyme Product Active Site
Enzyme: Peroxidase in liver cells Reactants: Hydrogen peroxide
Enzyme Reactants Hydrogen Peroxide Active Site
Enzyme: Peroxidase in liver cells Reactants: Hydrogen peroxide
Enzyme Reactants=Substrate Active Site
Enzyme: Peroxidase in liver cells Products: Water and Oxygen
Enzyme Product O 2 H 2 O Active Site
Enzyme: Peroxidase in liver cells Products: Water and Oxygen
Enzyme More Hydrogen Peroxide O 2 H 2 O Product Active Site
Macromolecules
• Carbohydrates • Lipids • Proteins • Nucleic Acids
Carbohydrates
• Made of Sugar • Main Source of energy • Examples: Sugar
Lipids
• 1 Glycerol & 3 Fatty Acids • Stores energy • Examples: Fats, Cholesterol
Protein
• Amino Acids • Makes up structures in body • Examples: Hair, muscles, skin, bones, etc.
Nucleic Acids
• Nucleotides • Store genetic material • Examples: DNA, RNA
Chemical Reactions and Enzymes D. Practice: balance the following equations
1) _ Cu + _ S
_ Cu 2 S 2) _ Na + _ O 2
_ Na 2 O 3) _ CuO + _ H 2
_ Cu + _ H 2 O