1. Heat Energy 2 Heat Capacities Sample Heat Capacity Problems
Latent Heat Capacity
Latent Heat Capacity Problems

2. Recall
That radiation is how heat is transferred to the Earth from the Sun.
Radiation is absorbed and reflected differently by various materials.
The amount of heat energy that materials can hold differs as well.  Specific Heat Capacity
The overall amount of heat energy (Q) an object can hold depends on
Mass (m)‏
Temperature change (ΔT)‏
Specific heat capacity for the material (c)‏

3. Thermal (Heat) Energy vs Temperature

4. Heat Capacity Problems
In order to solve a heat capacity problem we need to know 3 of the 4 variables
The temperature change also has its own formula
We will deal with 4 types of problems

5. Sample Problem 1 Find Q
How much heat energy is needed to heat 10 grams of water by 10 degrees?
The heat capacity of water is 4180

6. Sample Problem 2 Find m
If an amount ice is heated from -20 to -10 degrees with 100 joules of heat energy, how much mass must be present?
The heat capacity of ice is 2120

7. Sample Problem 3 Find ΔT
If a 10 g sample of water vapor absorbs 10 J of heat, by how much will its temperature increase?
The heat capacity of water is 2.02

8. Sample Problem 4 Find c
Given that a 10 g substance has its temperature raise by 10 degrees by absorbing 50 J of heat energy, what is the substances heat capacity?

9. The Other Half of the Heat Capacity Story
As a substance is heated through a phase transition, heat energy is absorbed from the surroundings as energy is used to break the intermolecular bonds.
Examples:
Ice  Water Water  Steam
The reverse also applies that a substance cooled through a phase transition will release heat as requires less energy in a more stable, bonded condition.
Water  Ice Steam  Water

10. Thermal (Heat) Energy vs Temperature

11. Latent Heat Capacity
How can we calculate the heat energy absorbed/released by a substance undergoing a phase transition?
Mass should still be a factor but there is no temperature change.
Scientists simply experimentally measure the amount of heat per mass.
Called latent heat capacity 
There is two latent heat capacities for each material; one for fusion (freezing) and one for vaporization.

12. Latent Heat Capacity Problems
Since there is only 3 variables, we will only have 3 types of problems to deal with.

13. Sample Problem 5 Find Q
What is the energy absorbed if 10 grams of ice is melted?
The is 333

14. Sample Problem 6 Find m
If it takes J to evaporate a sample of water what is the mass of the sample?
The is 2260

15. Sample Problem 7 Find ΔHfus
Given that a 10 g substance has released joules of heat energy by freezing, what is the substance’s latent heat capacity of fusion?

16. Why is This Stuff Important?
Sea Breezes
Moderating effects of lakes and oceans
Explains why winter lags the seasonal solar cycle.
Overall thermal regulation of the Earth