1. Unit 2 Chemistry Lesson 4 Changes in Matter Essential Questions: 1
Unit 2 Chemistry Lesson 4 Changes in Matter Essential Questions: 1.) What happens to a substance in a physical change? 2.) What happens to a substance in a chemical change? 3.) How are changes in energy and matter related?

2. Law of Conservation of mass- matter is not created or destroyed in any chemical or physical change
atoms are not lost or gained only rearranged

3. Conservation of Mass
Count the atoms of each element before and after the chemical change.

4. Temperature is related to the movement of particles in matter.

5. All chemical and physical change includes a change in energy
Energy and Matter
All chemical and physical change includes a change in energy
The ice absorbs energy from the surrounding matter.
When the wax burns, it gives off energy as light and heat.

6. Thermal energy- the total energy of the motion of all of the particles in an object
Thermal energy naturally flows from warmer matter to cooler matter.

7. 1.) Endothermic change- a change in which energy is absorbed
When ice melts, it absorbs thermal energy from its surroundings leaving the surroundings feeling cold.

8. 2.) Exothermic change- a change in which energy is released
Fireworks are an example of combustion. It releases thermal energy and light and heat.