1. Energy Ability to “do work” or produce a change. Forms: potential energy and kinetic energy Types: mechanical, electrical, nuclear, solar, chemical, etc.

2. Potential Energy -”stored” energy…due to position or composition. Chemical Energy: Energy stored in a substance due to its composition Types of atoms in substance Number and types of bonds Particular way the atoms are arranged

3. Kinetic Energy Energy of motion : Temperature – measures the average KE of the molecules in a sample. ALL matter is in constant motion and therefore has kinetic energy. How do gases, liquids, and solids compare?

4. Law Conservation of Energy In any chemical reaction or physical process, energy can be converted from one form to another, but it cannot be created nor destroyed. Food energy (sugar)  movement H 2 O and CO 2 and light  sugar (C 6 H 12 O 6 ) (C 6 H 12 O 6 )  H 2 O and CO 2 and (energy) Cell Respiration: Photosynthesis: in chloroplasts

5. Heat Energy Heat: “q” or “Q” calorie: amount of energy needed to raise the temperature of 1 gram H 2 O 1 ° C. 1000 cal = 1 kcal Calorie: nutritional or “food” calorie. (1 Cal = 1 kcal = 1000 cal ) Energy flowing from a warmer object to a cooler object. + Q means heat is “added” -Q means heat is “lost”

6. Converting Energy Units Energy Unit Conversions 1 Joule (J) = 0.2390 cal 1 calorie (cal) = 4.184J 1 kilojoule (KJ) = 1000 J 1 Calorie = 1 kcal (nutritional calorie) 1 kcal = 1000 cal

7. Nutritional Calorie A typical breakfast contains 230 nutritional Calories. Convert this to regular calories and Joules. 230 Cal x 1000 cal = 230,000 cal 1Cal 230,000 cal x 4.184 J = 960,000 J 1 cal

8. Specific Heat (C p ) The amount of energy required to raise the temperature of 1 g of ANY substance 1 ºC Measures a substances resistance to temperature change High C p = does NOT heat/cool rapidly Large Q change, small T change Low C p = heats/cools very quickly A little Q changes T a lot!!!

9. Specific Heat (C p ) Higher C p Lower C p Water in the gulf Sand on the beach GrassSidewalk Pizza CrustSauce ClothMetal Buckle

10. Specific Heat (C p ) Formula: Q = m · C p · ΔT Q = heat in Joules M = mass in grams C p = specific heat in J/g · ºC ΔT = change in temp (T final – T initial )

11. Ex: 10.0 g iron changed from 50.4 ºC to 25.0 ºC with a release of 114 J heat. Calculate C p.

12. Given: m = 10.0gWant: C = ? Ti = 50.4 ºC Tf = 25.0 ºC So ΔT = 25 – 50.4 = -25.4 ºC Q = -114 J (negative because it’s lost) Equ: Q = m C ΔT and C = Q m ΔT C = -114J = 0.449 J/g ºC (10.0g)(-25.4 ºC ) (Specific Heat is ALWAYS a (+) number!!)

13. If the temperature of 25g granite, which has a C p of 0.803 J/g · ºC is heated from 25 ºC to 55ºC, how much heat did the granite absorb?

14. If the temperature of 25g granite, which has a C p of 0.803 J/g · ºC is heated from 25 ºC to 55ºC, how much heat did the granite absorb? Given: m = 25gWant: Q = ? C = 0.803J/g ºC (expect + value) Ti = 25 ºC Tf = 55 ºC So ΔT = 55 – 25 = 30. ºC Equ: Q = m · C p ·ΔT Q = (25g)(0.803J/g ºC) (30. ºC) = 602J

15. A piece of metal with a mass of 4.68g absorbs 25 J of heat when its temperature increases by 182 °C. What is the specific heat of the metal?

16. Given: m = 4.68g Want: C = ? Q = 25 J (added) ΔT = 182 °C Equ: Q = m · C p ·ΔT and C = Q m ΔT C = 25 J = 0.029J/g °C (4.68g)(182 °C)