1. Mr. Quinn & Ms. Tom March 3, 2014 Aim: How does the temperature of water change as energy is transferred? Do Now: Why is it cooler at the beach in the summer and warmer in the winter? Why is the sand on the beach warmer than the water?

2. Introduction The key is SPECIFIC HEAT. Definition of “specific heat:” The amount of energy required to raise the temperature of one gram of a substance one degree Celsius. Q = mCΔt or Q = mC(t f -t i ) Q = heat M = mass C = specific heat Δt = change in temperature

3. Let’s Try It Out! What is the amount of heat energy released when 50.0 grams of water is cooled from 20.0°C to 10.0°C? (1) 5.00x10 2 J (3) 1.67x10 5 J (2) 2.09x10 3 J (4) 1.13x10 6 J

4. Let’s Try It Out! The temperature of a sample of water changes from 10°C to 20°C when the sample absorbs 418 joules of heat. What is the mass of the sample? (1) 1 g (3) 100 g (2) 10 g (4) 1000 g

5. Let’s Try It Out! A 10.0-gram sample of H 2 O (ℓ) at 23.0°C absorbs 209 joules of heat. What is the final temperature of the H 2 O (ℓ) sample? (1) 5.0°C (3) 28.0°C (2) 18.0°C (4) 50.0°C

6. Your Turn!

7. Let’s Try It Out! 7 a.m.3 p.m. Mass of Water (g) Temperature (°C) Mass of Water (g) Temperature (°C) 80012.580020.5 A student investigated heat transfer using a bottle of water. The student placed the bottle in a room at 20.5°C. The student measured the temperature of the water in the bottle at 7 a.m. and again at 3 p.m. The data from the investigation are shown in the table below. Water Bottle Investigation Data Compare the average kinetic energy of the water molecules in the bottle at 7 a.m. to the average kinetic energy of the water molecules in the bottle at 3 p.m. State the direction of heat transfer between the surroundings and the water in the bottle from 7 a.m. to 3 p.m. Show a numerical setup for calculating the change in the thermal energy of the water in the bottle from 7 a.m. to 3 p.m.

8. Let’s Try It Out! A 20.0-gram sample of H 2 O (ℓ) at 8.0°C absorbs 413 joules of heat. What is the final temperature of the H 2 O (ℓ) sample? (1) 5.4°C (3) 18.0°C (2) 12.9°C (4) 21.8°C

9. Let’s Try It Out! The temperature of a sample of water changes from 20°C to 40°C when the sample absorbs 836 joules of heat. What is the mass of the sample? (1) 1 g (3) 100 g (2) 10 g (4) 1000 g

10. Let’s Try It Out! What is the amount of heat energy released when 100.0 grams of water is cooled from 30.0°C to 10.0°C? (1) 5.30x10 2 J (3) 8.36x10 3 J (2) 3.39x10 3 J (4) 1.03x10 5 J