1. First Law of Thermodynamics
Heat ADDED to system:
Heat REMOVED from system:
Work done ON system BY environment:
Work done BY system ON environment:
ADD heat to system or do work ON system:
REMOVE heat from system or work done BY system:
 INCREASE internal energy
 DECREASE internal energy

3. Work
Force PARALLEL to displacement:
Force OPPOSITE to displacement:
Volume INCREASE
Volume DECREASE

4. (based on 20.27) The figure shows two processes, A and B, carried out on an ideal gas. Consider the following choices: A B
Same
Not enough information
In which process was the amount of work done by the gas greater?
In which process was the change in energy of the gas greater?
In which process was the energy transferred thermally to the gas greater?

5. What are Won, Qin, and DEint for this process?
Using a P-V diagram
Consider a monatomic ideal gas, that begins at an initial pressure and volume of 200 kPa and 0.01 m3 . The pressure and the volume of the gas are reduced as shown in the P-V diagram, to a final pressure and volume of 100 kPa and m3.
P, kPA
200
100
V, m3
What are Won, Qin, and DEint for this process?
.005
0.01
 Area under curve
= Area of rectangle + Area of Triangle
= –0.75 kJ
= kJ
Don’t forget the First Law!
= –2.25 kJ – (+0.75 kJ) = –3.0 kJ
= –2.25 kJ
Was heat added or removed during this process?

6. Constant Volume Process  NO WORK DONE
(monatomic)
Ideal Gas Processes – Special Case P V
 Area under curve
Constant Volume Process  NO WORK DONE

7. Constant Pressure Process
(monatomic)
Ideal Gas Processes – Special Case P V

8. NO CHANGE IN INTERNAL ENERGY
Constant Temperature Process
(monatomic)
Ideal Gas Processes – Special Case
Iso Thermal P V
Isothermal Process 
NO CHANGE IN INTERNAL ENERGY

9. Adiabat (Isentrope) STEEPER than Isotherm (through same point)
Isentropic (Adiabatic) Process
(monatomic)
Ideal Gas Processes – Special Case
Consider adiabatic expansion of gas: V P Vi Vf
Isotherm (high T)
Isotherm (low T)
Adiabat
Adiabat (Isentrope) STEEPER than Isotherm (through same point)

10. (based on 20.58) A sample of diatomic gas (d = 5, g = 5/3) begins in the state 1 shown on the PV diagram and ends in the state 3. Determine everything you can about states, changes in states, and processes.