1. Heat Capacity and Specific Heat
“Shadows”
Andy Warhol
1978

2. Heat Capacity
The amount of energy (heat) an object must absorb to increase in temperature 1°C.
Which would have a greater heat capacity, a glass of water or a lake?

3. Heat Capacity What do you think that the heat capacity depends on?
Composition (type of substance)
Mass (amount of substance)

4. Specific Heat Capacity (C)
Also called Specific Heat
The amount of energy needed to raise 1 gram of a substance 1 degree Celsius
ΔT is Tfinal - Tinitial
Units: cal/g°C or J/g°C
Don’t try to memorize this formula, use the units to show you the set-up!!!

5. Specific Heat Problems:
When 375 J of heat is added to a 45 g sample of metal its temperature increases by 5.2°C. What is the metal’s specific heat?
Answer: 1.6 J/g°C

6. Specific Heat Problems:
What is the specific heat of a material that requires J of energy to heat a 34.2 g sample up by 7.2°C?
Answer: 3.9 J/g°C

7. Rearranging Our Formula:
q = mCΔT
Allows you to calculate the heat flow for an object (system or surroundings)
If the temperature of a 25 g sample of water changes from 22.0C to 30.0C, how much heat energy did the water absorb? (Cwater = J/gC)
Answer: 840 J

8. Another Problem:
A 37.5 g piece of aluminum cools from 75.2°C to 22.0°C. If the specific heat of Al is 0.89 J/g°C, how much energy was lost?
Answer: q= J (neg. shows energy lost)