1. Warm Up 5.4: Determine if a Chemical or Physical Change 1.
An ice cube is placed in the sun. Later there is a puddle of water and then the puddle is gone. 2.
Two chemical are mixed together and a gas is produce. 3.
A bicycle changes color as it rusts. 4.
A solid is crushed to a powder. 5.
Two substances are mixed and light is produced. 6.
Mixing salt and pepper. 7.
Chocolate syrup is dissolved in milk. 8.
A marshmallow is burned over a campfire. 9.
A marshmallow is cut in half. P C C P C P P C P

2. Physical change effects….
Size
Shape
Color
State of matter
Additionally….
Reversible
No energy

3. Chemical Change effects…
Composition
Additionally…
Energy involved
New substance formed
Atoms rearranged

4. Signs of Chemical Change
Color change
Energy:
Light
Heat
Fire
Electricity
Gas production:
Bubbles
Fizzing
Smoke
Odor change
Precipitate

5. Basics Reactant Product New one or more substances
Change into
New
one or more substances
one or more substances
Reactant
Product

6. Law of Conservation of Matter/Mass
Matter is not created nor destroyed
Just rearranged
Total mass of reactants = total mass of products

7. Symbols used in equations
After a chemical formula:
(s) or ¯ : solid Cu(s) CaCo3 ¯
(g) or  : gas H2 (g) O2
(l) : liquid H2O(l)
(aq) : aqueous solution CaCl2 (aq)
dissolved in H2O

8. Other Symbols  or heat :heat supplied to rxn
Chemical formula : catalyst

9. All chemical rxns have…. a change in energy

10. Ea: activation energy: Energy needed to start reactant collisions thus starting the rxn Activated Complex: “top of the hill” reactants’ atoms rearrange due to collisions. H: Enthalpy: change in heat: products – reactants

11. Collision Theory ( 1:17 min)

12. Set up your paper Endothermic Exothermic Sign Need 1 line
Descriptive words
Need at least 2 lines
Drawing
need at least 6 lines
Reaction placement
Need 3 lines
Reaction path diagrams
Need at least 10 lines

13. Endothermic Exothermic system heat system heat
Endothermic
Exothermic
Sign
Descriptive Words
Drawing
“ Into”, absorb, heat added;
heat needed
Given off; heat produced; exit
system
heat
surroundings
system
heat
surroundings

14. Endothermic Exothermic
Reaction placement
Endothermic
A + B + heat  C or
A + B  C H= + kJ
Exothermic
A + B  C + heat or
A + B  C H= - kJ

15. Endothermic Exothermic“
Endothermic
Exothermic
Rxn Path diagram

16. Activated complex Activated complex Ea Ea H= - Products Reactants
Endothermic
Exothermic
Activated complex
Activated complex Ea Ea
H= -
heat
given
off
Products
Reactants
H= +
heat
added
Products
Reactants

17. Reactions Rates

19. Catalyst speeds up rxn w/o being used Less activation energy is needed
Lowers the activated complex

20. Other factors that effect rxn rate
Increase Temperature
Increase Pressure
Increase Concentration
amount of a substance per area
Bigger M = more concentration
Which will cause a faster reaction: 3M or 0.4M
3M will make the rxn faster