1. Chemical and Physical Change
The Nature
of Changes
in Matter

2. Types of Changes : Physical Change
The fundamental particles stay the same. Small change in energy
Evaporating, Dissolving, Melting, Freezing
Liquid water = H2O Ice = H2O
Chemical Change
Nuclear
Change

3. Types of Changes : Physical Change
The fundamental particles stay the same. Small change in energy
Evaporating, Dissolving, Melting, Freezing
Liquid water = H2O Ice = H2O
Chemical Change
A change in the bonds of a compound. New compound has its own properties. Medium change in energy
Produces light, instant heating or cooling
AlCl3  AlF3
Nuclear
Change

4. Types of Changes : Physical Change
The fundamental particles stay the same. Small change in energy
Evaporating, Dissolving, Melting, Freezing
Liquid water = H2O Ice = H2O
Chemical Change
A change in the bonds of a compound. New compound has its own properties. Medium change in energy
Produces light, instant heating
AlCl3  AlF3g or cooling
Nuclear
Change
Create a new element. Releases radiation. Huge change in energy
H + Proton = He

5. Kinetic Molecular Theory
All matter is made of particles
Smallest particles of matter are constantly moving
Smallest particles = Elements and Compounds

6. Why Do Chemical Reactions Occur
Explained by the kinetic molecular theory
The random motion of particles results in collisions between the particles

7. collision-reaction theory
Collision-reaction theory: Explains when these collisions result in chemical reactions
1) Orientation: Has to collide the right way
2) Energy: Needs enough energy to break bonds
Orientation + Energy = rearrangement of particles

9. Chemical Reactions
Chemical Reaction = Chemical change Evidence of Chemical Reactions
Evidence
Description and Example
Color Change
Final product is a different color then the starting material

10. Chemical Reactions
Chemical Reaction = Chemical change Evidence of Chemical Reactions
Evidence
Description and Example
Color Change
Final product is a different color then the starting material
Odor Change
Final product has a different odor then the starting material

11. Chemical Reactions
Chemical Reaction = Chemical change Evidence of Chemical Reactions
Evidence
Description and Example
Color Change
Final product is a different color then the starting material
Odor Change
Final product has a different odor then the starting material
State Change
Final product may be a different phase than the starting material

12. Chemical Reactions
Chemical Reaction = Chemical change Evidence of Chemical Reactions
Evidence
Description and Example
Color Change
Final product is a different color then the starting material
Odor Change
Final product has a different odor then the starting material
State Change
Final product may be a different phase than the starting material
Energy Change
Heat, energy, sound, or light energy is either released (exothermic reaction) or absorbed (endothermic)

13. Chemical Reactions
What if there is no obvious evidence of Chemical Reactions
May require a chemical analysis (diagnostic test) if no observable change occurred

14. Conversion of Mass in Chemical Change
Conservation of mass: The mass of the reactants is equal to the mass of the products Law of Conservation of Matter: Matter cannot be created or destroyed. If you start with g your will finish with g

15. Showing the conservation of mass in an equation
Conservation of Mass: Next class