1. Topic: Energy Do Now: 1. Take out HW and open up your notes from yesterday

2. All physical & chemical changes are accompanied by change in energy The chemistry of energy changes is known as Thermochemistry!

3. Energy: Ability to do Work The SI unit for an energy measurement is called the Joule (J) EXAMPLE: 1 Joule = amount of energy required to lift a golf ball 1 meter

4. Other Energy Units: Other Energy Units: calorie, Calorie, BTU’s calorie, Calorie, BTU’s 1 calorie = 4.18 Joules 1 calorie = 4.18 Joules 1 Calorie = 1000 calories = 1 kilocalorie 1 Calorie = 1000 calories = 1 kilocalorie

5. There are 2 types of energy (we are going to draw another chart – like the on we did for matter – in our notebook

6. (Not a complete list!) Energy Mechanical – large enough to see KineticPotential Non-mechanical – too small to see ChemicalHeatLightElectricalNuclear

7. Kinetic Energy (KE) – makes things move KE = ½ x Mass x Velocity 2 = ½ mV 2 KE depends on how heavy and how fast

8. Potential Energy (PE): stored energy of matter

9. When Potential energy is released from matter it becomes kinetic energy

10. Chemical Energy energy stored in bonds; it is released as the result of a chemical reaction

11. Heat Energy Energy related to the changes in temperature

12. Light Energy – makes things visible

13. Electrical Energy – result of the flow of electrons

14. Nuclear: energy is released by the change in the nucleus of an atom (can be very explosive)

15. Law of Conservation of Energy Energy is neither created nor destroyed in ordinary chemical or physical change Energy before = Energy after Energy can be converted from one form to another - potential to kinetic- radiant to electric - electric to heat- chemical to kinetic - chemical to electrical

16. Energy of Universe is conserved Universe Environment System Energy Energy can move between the system and the environment

17. Two ways to classify chemical reaction: 1. energy (heat) is given off = exothermic 2. energy (heat) is absorbed = endothermic

18. Exothermic – releases heat to environment QUESTION: What happens to the temperature of the environment? QUESTION: What happens to temperature of system?

19. a Environment System Energy EXO - energy leaves system (exits) Temperature of environment  Temperature of system 

20. Endothermic – heat is absorbed by the system QUESTION: What happens to the temperature of the environment? QUESTION: What happens to temperature of system?

21. Endo - Energy enters system (enter) Environment System Energy Temperature of environment  Temperature of system 

22. Note: Heat flows from hotter object to cooler object Example; Cold pack on leg: Heat flows from the leg to the cold pack! – Leg cools down; cold pack warms up