1. Endothermic/ Exothermic

2. Entry Task Monday May 2 nd List something that feels warm and a something that feels cold

3. Agenda Grade slips Last day for test corrections on Thursday! Lemonade Probe Notes on endotherminc/exothermic Heat flow ws- Due at the end of the period!

4. What is Heat? Heat is the motion of molecules Hot molecules move fast while cold molecules move slowly Heat is symbolized by the letter q (the amount of heat energy in a system)

5. What is Heat? Everything has heat energy- even cold things! https://www.youtube.com/watch?v=f1eAOygDP5s

6. The Flow of Heat Heat is transferred when hot molecules bump into colder molecules (like billiard balls) Heat is always transferred from hot molecules to cold molecules until they are the same temperature

7. Measuring Heat Heat either flows from a system to the surroundings or from the surroundings to a system. Heat energy is measured in units called a Joule- pronounced “Jewel”

8. Exothermic Heat energy is given off Heat energy EXits the system to the surroundings Surroundings will feel warmer Q is negative (system is spending heat)

9. Examples of Exothermic Processes Combustion Freezing water Rusting Iron Mixing water with calcium chloride

10. Endothermic Heat energy is absorbed Heat energy moves ENto the system from the surroundings Surroundings will feel colder as the heat is absorbed Q is positive (system is increasing in heat)

11. Examples of Endothermic Processes Photosynthesis Mixing water and ammonium nitrate Baking bread Evaporation of water

12. Example problem 1 Process: Cooking an egg System: Surroundings: Does the system release or absorb heat?: Is Q positive or negative?: Endothermic or exothermic?: Egg Hot frying pan Egg Absorbs Heat Positive Endothermic

13. Example problem 2 Process: Burning a match System: Surroundings: Does the system release or absorb heat?: Is Q positive or negative?: Endothermic or exothermic?: Match Air Match Releases Heat Negative Exothermic

14. Example problem 3 Process: Melting Ice in a Drink System: Surroundings: Does the system release or absorb heat?: Is Q positive or negative?: Endothermic or exothermic?: Ice Surrounding liquid Ice Absorbs Heat Positive Endothermic