1. Chapter 9
Heat

2. Heat Temperature and Thermal Equilibrium Defining Heat
Changes in Temperature and Phase

3. Temperature

4. Temperature and Kinetic Energy
Temperature = A measure of the average kinetic energy of the particles in a substance
For monatomic gas  translational KE

5. For polyatomic substances…

6. Internal Energy
Internal energy (U) = the total energy of a substance due to the KE and PE of its particles
Internal energy depends on mass and temperature
For an ideal gas, internal energy is proportional to just temperature

7. Temperature & Internal Energy
Distinguish between temperature and internal energy
Which depends on mass?
Compare T and U for…
1 cup of 20°C and 1 cup of 25°C
1 cup of 20°C and ½ cup of 20°C
1 cup of hot tea and a swimming pool of cold water

8. Thermal Equilibrium
Thermal equilibrium = the state in which two bodies in physical contact with each other have identical temperatures

9. Thermal Expansion
Generally, at constant pressure, an increase in temperature causes an increase in volume
Exception?
Compare gases, liquids, and solids

10. Temperature Units
Celsius (°C)
Fahrenheit (°F)
Kelvin (K)

11. Another important point to know: Absolute zero = 0 K

12. Temperature Conversions
𝑇F= 9 5 𝑇C+32.0
𝑇=𝑇C
𝑇F = Fahrenheit temperature
𝑇C = Celsius temperature
𝑇 = Kelvin temperature

13. Heat
Heat = the energy transferred between objects because of a difference in their temperatures
Energy transferred as heat moves from an object with higher temperature to an object with lower temperature

15. What is happening on a macroscopic scale?
What is happening on a microscopic scale?
(What is happening with temperature, internal energy, and heat?)

17. Heat = Q

18. 3 Types of Heat Conduction Convection Radiation Requires contact
Consider conductivity
Convection
Fluid movement
Radiation
Electromagnetic waves

20. Conservation of Energy
Δ𝐾𝐸+Δ𝑃𝐸+Δ𝑈=0

21. Specific Heat Capacity
Specific heat capacity = the quantity of heat required to raise 1 kg of a substance by 1 K or 1°C given constant pressure and volume Units: J/kg·°C
𝑐 𝑝 = 𝑄 𝑚Δ𝑇

23. Calorimetry = an experimental procedure used to measure the energy transferred from one substance to another as heat

24. 𝑄 𝑤 =− 𝑄 𝑥 𝑐 𝑝,𝑤 𝑚 𝑤 Δ 𝑇 𝑤 =− 𝑐 𝑝,𝑥 𝑚 𝑥 Δ 𝑇 𝑥 energy absorbed by water
energy released by substance =
𝑄 𝑤 =− 𝑄 𝑥
𝑐 𝑝,𝑤 𝑚 𝑤 Δ 𝑇 𝑤 =− 𝑐 𝑝,𝑥 𝑚 𝑥 Δ 𝑇 𝑥
Compare the final temperatures of the water and the substance

26. Latent Heat
Latent heat (L) = the energy per unit mass that is transferred during a phase change of a substance
Latent heat
𝑄=𝑚𝐿
Heat of fusion
Solid/liquid
𝐿 𝑓
Heat of vaporization
Liquid/gas
𝐿 𝑣