Specific Heat – Problems
SEE THE BACK OF THIS HANDOUT FOR SAMPLE PROBLEMS
Q = cm∆t, where:
Q = heat energy in calories
c = specific heat capacity (water is defined as 1 cal/g°C)
m = mass in grams
∆t = change in temperature in degrees Celsius
Also note: 1 kg (kilogram) = 1000 grams = 2.2 pounds
- A hot potato is put into a cold glass of 20°C water. After the potato and the water have come to a common temperature, the thermometer reading of the water is found to be 23°C. Knowing the mass of the water to be 250 grams, find the amount of heat Q received by it.
- 3,000 calories of energy are added to 500 grams of water that originally has a temperature of 40°C. What will be the final temperature of the water?
- The sun shines on a small 300 liter (which is the same as 300 kilograms) pool of water all day long until the temperature of the pool goes from 20°C in the morning to 35°C in the evening. How much heat energy did the sun give to the water in the pool?
- A very hot chunk of concrete at 500°C that weighs 800 grams is dropped into a bucket containing 3 liters of water. The final temperature of the water and the concrete is 98°C. The specific heat of concrete is 0.72 cal/g°C. How much does the temperature of the water increase? (Hint: first find out how much heat the chunk of concrete loses to the water, then calculate how much that heat changes the temperature of the water.)