1. UNIT 12: PHYSICAL & CHEMICAL CHANGES
PHASES CHANGES SYNTHESIS
DISSOLUTION DECOMPOSITION
DEFORMATION OXIDATION
PRECIPITATION
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2. PHYSICAL CHANGES
Does not affect the nature or the characteristic properties of a substance or matter
Are reversible
3 Types:
1 – Changes of State
2 – Dissolution
3 – Deformation

3. CHANGES OF STATE There are three states (or phases): 1 – Gas
2 – Liquid
3 – Solid
A phase change occurs when matter transforms from one state to another
This form of change IS reversible (Physical)

4. CHANGES OF STATE ROLE OF ENERGY Adding Energy 1- Increases movement
2- Releases attraction
Subtracting Energy
1- Decreases movement
2- Creates attraction

5. DISSOLUTION Creating a solution by dissolving a SOLUTE into a SOLVENT
Why is this a PHYSICAL CHANGE?
EX. When a cube of sugar dissolves into water, the sugar molecules break up and are uniformly distributed within the water. BUT, the sugar molecules and water molecules DO NOT CHANGE

6. DISSOLUTION ROLE OF ENERGY Affects Temperature of solution
Affects Solubility of
solution
ENERGY TRANSFER
RESULT
DISSOLUTION RELEASES ENERGY
TEMPERATURE INCREASES
DISSOLUTION ABSORBS ENERGY
TEMPERATURE DECREASES

7. DEFORMATION Changes the shape of the material
Some are reversible. Some are permanent

8. DEFORMATION ROLE OF ENERGY: Always involves ENERGY Transfer
One force imposing on another object transferring that energy it had

9. CHEMICAL CHANGES
Changes the nature and characteristic properties of a substance or matter.
Are Irreversible
Creates new material
or substance
4 TYPES:
1- SYNTHESIS 2- DECOMPOSITION
3- OXIDATION 4- PRECIPITATION

10. CHEMICAL CHANGES 𝐻 2 + 𝐶𝑙 2 = 2 HCl + energy + = +
2 HCl breaks down proteins in your stomach to prepare them for digestion and kills bacteria that enter your stomach. + = +
ENERGY

11. CHEMICAL CHANGES
There are many clues that help tell the difference between CHEMICAL & PHYSICAL changes
1- the release of gas
2- greater changes of heat
3- the generation of light
4- a change of colour
5- the formation of a precipitate

12. SYNTHESIS
The formation of a complex molecule from atoms or simpler molecules
2 𝐻 𝑂 𝐻 2 𝑂 + Energy
(synthesis of water releases a lot of energy)
𝑁 𝑂 2 + Energy 2 𝑁𝑂 2
(synthesis of Nitrous Dioxide absorbs energy)

13. SYNTHESIS A major chemical reaction is the process of PHOTOSYNTHESIS
CARBON DIOXIDE and WATER along with the suns energy come together to make SUGAR and OXYGEN.
6 𝐶𝑂 𝐻 2 𝑂 + Sun 𝐶 6 𝐻 12 𝑂 𝑂 2

14. DECOMPOSITION
The transformation of complex molecules into simpler molecules or atoms
The opposite of SYNTHESIS.
Role of Energy: Breaks down the molecules
2 𝐻 2 𝑂 + electrical energy 𝐻 𝑂 2

15. DECOMPOSITION The opposite of PHOTOSYNTHESIS is CELLULAR RESPIRATION.
A process that involves Oxidation.
𝐶 6 𝐻 12 𝑂 𝑂 𝐶𝑂 𝐻 2 𝑂 + energy
SUGAR and OXYGEN becomes CARBON DIOXIDE and WATER plus ENERGY
Respiration releases energy.
Photosynthesis absorbs energy.

16. OXIDATION
A chemical reaction involving oxygen or a substance that has similar properties to oxygen
IRON combines with OXYGEN to form IRON OXIDE (RUST)
4 Fe + 3 𝑂 𝐹𝑒 2 𝑂 3 + energy

17. PRECIPITATION
The formation of a solid that is less soluble, or not soluble, following the mixing of the two solutions.
Addition of ENZYMES. (milk curdles into cheese)