1. REVIEW FOR QUIZ
HEAT

2. Heat is measured in ____ and is represented with the symbol ___.
Temperature is measured in ___.
Mass is measured in ____.
Specific heat is measured in ___ and is represented with the symbol ____.
Joules, Q
Degrees Celsius
Grams
J/g°C, c

3. You eat a snack that is 20 g carbs, 4 g fat and 1 g protein
You eat a snack that is 20 g carbs, 4 g fat and 1 g protein. Give the total calories for each macromolecule and then give the total calories for the snack.
20 x 4 = 80 Calories
4 x 9 = 36 Calories
1 x 4 = 4 Calories
Total = 120 Calories

4. 1000 calories = 1 kCal = 1 Calorie 1 calorie= 4.184 Joules
Convert the following:
120 J = ___ calories
250 Calories = ____ energy calories
120 J cal_ = 28.7 cal
4.184 J
250 C cal = 250,000 cal 1C

5. How many joules of energy are absorbed by 250g of water if its temperature rises from 30.0°C to 95.0°C?
Q= mcΔT
Q = (250g)(4.184J/g°C)(65°C)
Q= 67,990 J
Convert this answer into nutritional calories (c)
67,990J cal C____ C
4.184J cal

6. How many Joules of energy are released if a block of metal that weighs 250 g with a specific heat of J/g°C is cooled from 400 °C to 285°C ?
Q= mcΔT
Q = (250 J)(0.234J/g°C)(115°C)
Q = 6,727.5 J

7. What is the specific heat of a 50 g piece of metal that takes 300 J of energy to raise the temperature by 40°C?
Q= mcΔT
300 J = (50 g)(c)(40°C)
c = 0.15 J/g°C

8. You place a 450 g block of metal in a beaker until the metal reaches a temperature of 85°C. You place the metal in a 250 mL of water in another beaker and measure the temperature to be 30.0°C. When the metal is placed into the water, the final temperature of the system reaches 37.5°C. What is the specific heat of the metal?
mcΔT = mcΔT
(450g)(c)(47.5°C) = (250g)(4.184J/g°C) (7.5°C)
0.42J/g°C