1. Changes in Matter
Matter Lecture 2

2. Physical Change No new substance is formed Examples:
Change of color (with no change in composition)
Grinding of substances into powders

3. Change of phase/state (solid, liquid, gas)
Dependent on temperature and pressure

4. Phase Changes

5. Chemical Change
Process that involves one or more substances forming something new
Always produces a change in properties
Examples:
Rusting of iron
Souring of milk
Burning of paper

6. Chemical Reaction Chemical changes are chemical reactions
Reactants  products

7. Law of Conservation of Mass
Matter cannot be created or destroyed
True for all chemical and physical changes
Massreactants = Massproducts
Example:
If 11.2 g of hydrogen and 88.8 g of oxygen react to form water, how much water will be formed?

8. Both chemical and physical changes involve changes in energy…
Endothermic
Absorbs energy
Examples:
Melting ice
Water absorbs energy to break down into oxygen and hydrogen gas
Exothermic
Releases energy
Burning paper
Freezing water