1. Reaction Energy and Reaction Kinetics Chapter 17 Notes

2. Units for Heat calorie (cal) = the amount of heat needed to raise the temperature of 1 gram of water by 1 o C. The “c” is ALWAYS lowercase for this unit. Calorie (Cal) = 1 kilocalorie (kcal). This is what we mean when we talk about food – how much energy is in the food. The “C” is ALWAYS capitalized! Joule = SI unit for energy, including heat

3. Heat Capacity The amount of heat needed to change an object’s temperature. This depends on – Size of the object – Material of the object – How big is the temperature change To allow more direct comparisons we use specific heat capacity instead.

4. Specific Heat Capacity The amount of heat need to change the temperature of 1 gram of a material by 1 o C – For water, c = 4.18 J/g∙ o C – This means it takes 4.18 joules of energy to raise the temperature of 1 gram of water from 20 o C to 21 o C You have been given a table of specific heats. This needs to go in the references section of your binder.

5. Calculating Specific Heat Heat (J or cal) Change in temperature = T final – T initial ( o C or K) Mass (g) Specific heat (J/g∙ o C or cal/g∙ o C)

6. Example 1 The temperature of a piece of copper with a mass of 95.4 grams increases from 25.0 o C to 48.0 o C when the metal absorbs 849 J of heat. What is the specific heat of copper?

7. Example 1 The temperature of a piece of copper with a mass of 95.4 grams increases from 25.0 o C to 48.0 o C when the metal absorbs 849 J of heat. What is the specific heat of copper?

8. Example 1 The temperature of a piece of copper with a mass of 95.4 grams increases from 25.0 o C to 48.0 o C when the metal absorbs 849 J of heat. What is the specific heat of copper?

9. Example 2 How much heat is required to raise the temperature of 250.0 g of mercury 52.0 o C?

10. Example 2 How much heat is required to raise the temperature of 250.0 g of mercury 52.0 o C?

11. Example 2 How much heat is required to raise the temperature of 250.0 g of mercury 52.0 o C?

12. Example 3 What is the temperature change when 2543 J of heat are added to 76.4 g of alcohol?

13. Example 3 What is the temperature change when 2543 J of heat are added to 76.4 g of alcohol?

14. Example 3 What is the temperature change when 2543 J of heat are added to 76.4 g of alcohol?

15. Example 4 The temperature of a 283 gram sample increases 11.2 o C by absorbing 1204 J of heat. What material is the sample?

16. Example 4 The temperature of a 283 gram sample increases 11.2 o C by absorbing 1204 J of heat. What material is the sample?

17. Example 4 The temperature of a 283 gram sample increases 11.2 o C by absorbing 1204 J of heat. What material is the sample?