1. Thermal Properties of Matter

2. Thermal Energy
Thermal energy is transferred in one of three ways: conduction, convection, and radiation.
Conduction
Convection
Radiation

3. Conduction
Conduction - is the process by which heat energy is transmitted through direct contact between neighboring molecules. 

4. Convection
Convection - is heat transfer by the circular motion of a fluid such as air or water. It is caused by the hot less dense material rising and the cool more dense material sinking.

5. Radiation
Radiation – is heat transfer due to emission of electromagnetic waves.

6. Change in State Endothermic – Energy is added to the system
Exothermic – Energy is removed from the system
Process
Change of State
Energy Change
Melting
Solid to Liquid
Endothermic
Freezing
Liquid to Solid
Exothermic
Vaporization
Liquid to Gas
Condensation
Gas to Liquid
Sublimation
Solid to Gas
Deposition
Gas to Solid

7. Thermal Properties
Some objects transfer thermal energy very easily and other object objects prevents the transfer of heat. We call these conductors or insulators.

8. Conductor
Conductor – is a material that allows energy in the form of heat, to be transferred within the material, without any movement of the material itself.

9. Conductors
What are some examples of objects that conduct heat easily? When is using a thermal conductor useful?

10. Insulator
Insulator – is something that prevents heat from moving from one place to another.

11. Insulators
What are some examples of objects that insulate the transfer of heat? When is using a thermal insulator useful?

12. Heat Capacity
Heat capacity, c, is the amount of heat or energy required to raise the temperature of an object.
𝑐 = 𝑄 mΔ𝑇
Q – Energy (J)
ΔT – change in temperature (K or ºC)
m – mass (kg or g)

13. Heat Capacity Conductors have a low heat capacity.
Insulators have a high heat capacity.
Substance
Heat Capacity (J/gºC)
Heat Capacity (J/kgK)
Water
4.184
4184
Ice
2.010
2010
Water Vapor
Dry Air
1.020
1020
Iron
0.444
444
Copper
0.385
385
Lead
0.160
160
Gold
0.129
129

14. Practice Problems
A 20 g sample of an unknown metal increases its temperature from 30 ˚C to 40 ˚C when 88 J of energy is added to it. Find the specific heat and identify the metal.
While hiking you find a gold colored coin. You can find out if it is real gold by finding its specific heat. You apply 20 J of energy to the 2.5 g coin and the temperature rises 5 ˚C. Is the coin gold?

15. Practice Problems
You find another coin that has a mass of 2.5 g. When you apply 20 J to the coin it rises ˚C. What is the material of the coin?
You are very thirsty and find a clear odorless liquid, but you’re not sure if it is water. You gather a 10 g sample of the liquid and apply J of energy to the liquid and the temperature increases 5 ˚C. Is the liquid water?

16. Thermal Energy
We can also find the amount of energy required to change an objects temperature. 𝑄=𝑐𝑚Δ𝑇 Q – Energy (J) c – Specific Heat (J/gºC) m – mass (kg or g) ΔT – change in temp. (K or ºC)

17. Practice Problems
You would like to cook some Macaroni and Cheese, but first you need to boil the water. How much Heat energy (J) is required in order to boil (100 ˚C) a liter (1000 g) of water from room temperature (30 ˚C)?
You leave 20 pennies predating 1982, so they are solid copper. How much energy from the sun does it take to raise the temperature of the 50 g of copper pennies from 30 ˚C to 40 ˚C?

18. Practice Problems
Ice cream is frozen heavy cream or other milk products, which have a specific heat of 3.1 J/g˚C. In order to make ice cream you need to remove energy by dropping the temperature from 25 ˚C to -5 ˚C. How much energy must be removed to make 1 kg of ice cream?
Poultry product are not safe to eat unless cooked to 71 ˚C. If chicken has a specific heat of 2.72 J/g˚C, how much energy is necessary to cook a 170 g chicken breast from 27 ˚C?

19. Thermal Energy
We can also find the change in temperature in object will have when energy is applied to the object. Δ𝑇= 𝑄 𝑐𝑚 Q – Energy (J) c – Specific Heat (J/gºC) m – mass (kg or g) ΔT – change in temp. (K or ºC)

20. Practice Problems
If you add 603 J of heat to 100 g of ice will it melt if it was originally at -5 ˚C?
If you add J of heat to a 500 g iron skillet that was originally 30 ˚C would the skillet be hot enough to boil water?

21. Practice Problems
A 12.9 gram sample of an unknown metal at 26.5°C is placed in a Styrofoam cup containing 50.0 grams of water at 88.6°C. The water cools down and the metal warms up until thermal equilibrium is achieved at 87.1°C. Assuming all the heat lost by the water is gained by the metal and that the cup is perfectly insulated, determine the specific heat capacity of the unknown metal. The specific heat capacity of water is 4.18 J/g/°C.