1. 6.2 CHEMICAL REACTIONS
WHAT YOU WILL LEARN
-the parts of a chemical reaction
-how energy changes relate to chemical reactions
-the importance of enzymes in organisms
MAIN IDEA:
Chemical reactions allow living things to grow, develop, reproduce, and adapt

2. REACTANTS/PRODUCTS
CHEMICAL REACTION--process in which atoms are reorganized to make new substances:
CH4 + 2O → CO2 + 2H2O
REACTANTS → PRODUCTS
-subscript: # of atoms
-coefficient: # of molecules
-: direction of reaction
EXPLAIN: What is the relationship between a chemical bond and a chemical reaction?
-chemical BONDS created/broken by chemical REACTIONS

3. REACTANTS/PRODUCTS
CONSERVATION of MASS MATTER cannot be created or destroyed -atoms are NOT __________ or __________ # atoms in REACTANTS = # atoms in PRODUCTS VIDEO CLIP
created
destroyed

4. BALANCE EQUATIONS ____Mg + ____HCl  ____MgCl2 + ____ H2 Mg= Mg=
1- DETERMINE # atoms for each element –track w/tallies
2- PICK an element that is NOT equal on both sides of the equation
3- ADJUST your # atoms on each side of equation so both are equal
4- USE coefficients to show the # of atoms of each element on each side
____Mg + ____HCl  ____MgCl2 + ____ H2
Mg= Mg=
H= H=
Cl= Cl=
____H2O2  ____H2O + ____O2
H= H=
O= O=
EXPLAIN why chemical equations must be balanced:
-matter neither created or destroyed

5. BALANCE EQUATIONS
____N2 + ____H2 → ____NH3 ____HCl + ____NaOH → ____NaCl + ____H20 ____C6H12O6 +____O2 → ____CO2 + ____H20

6. ENERGY of REACTIONS
ENDOTHERMIC REACTIONS: -absorbs energyCOLD -need MORE energy to form new bonds in products Ex: photosynthesis EXOTHERMIC REACTIONS: -releases energyHOT -need MORE energy to break bonds in reactants Ex: sodium + chlorine  table salt DEMO

7. ENERGY of REACTIONS
ENDOthermic EXOthermic

8. ENERGY of REACTIONS EXOthermic -EXOthermic reaction:
EXPLAIN why energy of product might be LOWER than the energy of reactants-
-EXOthermic reaction:
energy in form of heat/light is released during reaction

9. -absorbs energy (HEAT)
ENERGY of REACTIONS endo or exo?
-barium hydroxide (s) + octahydrate (s) + ammonium thiocyanate (s)
-barium thicyanate + ammonia (g) + water (l)
Ba(OH)2 + 8H2O + 2NH4SCN  Ba(SCN)2 + 10H2O +2NH3
DEMO
ENDOTHERMIC
-absorbs energy (HEAT)

10. -release energy (HEAT)
ENERGY of REACTIONS endo or exo?
-hydrogen peroxide (l) + iodine (l) iodine (l) + water (l) + oxygen (g)
aka- elephant toothpaste
DEMO
EXOTHERMIC
-release energy (HEAT)

11. ENZYMES
activation energy: -least amount energy needed to start a reaction CATALYST -substances that __________activation energy needed -anything that ________________ a chemical reaction
LOWERS
speeds up

12. Each ENZYME usually “participates” in ONE type of reaction
ENZYMES
Enzyme ANIMATION -special proteins -biological catalysts -COMPOSED OF: -protein -PURPOSE: -speeds up rate of chemical reactions in biological process -REUSABLE: -YES--not used up in reaction -ACTIVITY LEVEL AFFECTED/INFLUENCED BY: -pH, temperature, other substances NATURALLY PRESENT in FRUIT / RAW FOOD
-lower activation energy needed
-speeds up reactions in living things
Each ENZYME usually “participates” in ONE type of reaction

13. ENZYMES LABEL 3 parts of process with brief description
substrates—REACTANT  substrate binds to active site in enzyme enzyme changes shape enzyme releases product
ANALOGY:
PUZZLE--right pieces fit--bend puzzle to change shape--pieces will pop out

14. ENZYMES/ BIOLOGICAL ENZYMES
NAME some biological processes that require enzymatic activity-
-muscle contraction
-cell division
-digestion

15. ENZYMES/ BIOLOGICAL ENZYMES: (EX/uses)
PROTEASE
-secreted in pancreas / activated in small intestine
-break down proteins
-amino acids needed for body
AMYLASE
-produced by pancreas /present in saliva
-breaks down starch to sugar
LIPASE
-produced by the pancreas
-break down fats
-used in digestion

16. REVIEW/PRACTICE
1- What principle can be applied to all chemical reactions?
conservation of mass reactants formed from products coefficient principle
2- The minimum amount of energy needed for a chemical reaction is called:
principle mass absorbent energy activation energy
3- What is the function of the enzyme-substrate?
destroy the enzyme break and form chemical bonds stop chemical reactions
4- In which of the following are bonds broken and new bonds formed?
polar molecules chemical reactions isotopes
5- Which statement is true of chemical reactions?
bonds break in reactants  bonds break in products products have fewer atoms than reactants

17. REVIEW/PRACTICE
6-DESCRIBE the importance of enzymes to living organisms -speeds up biological chemical reactions 7- IDENTIFY/DESCRIBE 2 factors that can influence enzyme activity. -temp, pH, substrate concentration

18. REVIEW/PRACTICE
10- DESCRIBE the effect temperature has on the rate of the reactions.
 -temp increases the rate of both reaction within specific ranges
9- INFER which enzyme is more active in a human cell
Enzyme A Enzyme B
EXPLAIN why-
-maximal activity around 37ºC

19. 6.2 CHEMICAL REACTIONS
AFTER YOU READ
Explain the role of chemical reactions in living things
All processes in living things are controlled by chemical reactions

20. REACTANTS/PRODUCTS reactants → products
BONDS in REACTANTS molecules/compounds break 
ATOMS rearrange
new bonds form in PRODUCTS
CH4 + 2O → CO2 + 2H2O
reactants → products
subscript: # atoms in molecule
coefficient: # of molecules

21. REACTANTS/PRODUCTS
CALCULATE the number of atoms of each element in the chemical equation:
CH4 + 2O → CO2 + 2H2O
ANAYLYZE—is equation balanced?
STATE principle that explains why
# atoms in reactants = # atoms in products
Element symbol
Element name
# atoms in REACTANT
# atoms in PROCUCT C
carbon H
hydrogen O
oxygen

22. ENZYMES
MATCHING
-____________min energy required for reactants to form products
-____________substance lowers energy needed to start reaction
-____________protein that is biological catalyst
-____________molecule binds to an enzyme
act energy
catalyst
enzyme
substrate

23. Energy of PRODUCT is HIGHER than energy of REACTANTS
ENERGY of REACTIONS
EXOTHERMIC REACTION  Energy of PRODUCT is LOWER than energy of REACTANTS
ENDOTHERMIC REACTION 
Energy of PRODUCT is HIGHER than energy of REACTANTS
energy is released
gets HOT
energy is absorbed gets COLD
DEMO

24. ENERGY of REACTIONS EXOTHERMIC—release energy HOT
ENDOTHERMIC—absorb energy
COLD

25. ENZYMES SUMMARIZE: Reusable? Composed of: yes proteins ENZYMES
Activity level
affected by:
temp/pH
Purpose:
speed up reactions
PARTICIPATES IN HOW MANY DIFFERENT TYPES OF REACTIONS?
1-Specific to each enzyme

26. ENZYMES
INTERPRET: pathway of reaction with an enzyme present

27. ENZYMES
ILLUSTRATE enzyme-substrate complex in cartoon form

28. ENZYMES
ANALYZE the role of catalysts in chemical reactions -speed up the reaction DESCRIBE the importance of enzymes in living organisms -allow all biological functions to occur