1. Chapter 16 Energy

2. Energy Energy= ability to do work or produce heat Heat = form of energy that flows from warmer to cooler object James Joule was first person to connect energy and heat Joule (J) = metric unit of heat and energy –It takes 4.184 joules to move 1 kg 1 meter in 1 second

3. Types of Energy Potential energy –Energy of position –stored in chemical bonds Kinetic energy –Energy of motion –formed when chemical bonds are broken

4. Potential Energy Potential energy is determined by type and number of chemical bonds –Helps explain why diesel (which has more bonds) trucks can get same gas mileage as octane (gas) cars

5. Law of Conservation of Energy Energy is never created nor destroyed but it can change forms Energy is usually lost in the form of heat Car engine converts about 37% of energy into movement –Feel the top of the hood after driving –Most energy is lost as heat

6. Measuring Heat calorie –Amount of heat needed to raise the temperature of 1 gram of pure water 1°C Food Calorie = 1000 calories You need to memorize the following conversions! –1 Calorie = 1000 calories = 1 kilocalorie –4.184 joules = 1 calorie –1000 joules = 1 kilojoule

7. How to solve heat problems Dimensional Analysis -process of canceling out units Set up all ratios with units NOT numbers Set up all ratios with units NOT numbers Plug in numbers Plug in numbers Multiply everything on the top of fraction Multiply everything on the top of fraction Multiply everything on the bottom of fraction Multiply everything on the bottom of fraction Divide Divide

8. 1. Convert 10 calories to joules 2. Convert 10 joules to calories

9. 3. Convert 3000 joules to kilojoules 4. Convert 3000 calories to kilocalories

10. 5. Convert 3000 calories to Calories 6. Convert 3000 calories to kilojoules

11. 7. Convert 3000 joules to kilocalories 8. Convert 3000 joules to Calories

12. 9. Convert 10 kilojoules to kilocalories 10. Convert 10 Calories to kilojoules

13. 11. Convert 3000 calories/minute to joules/hour 12. Convert 10 kilojoules/minute to kilocalories/hour