- 1st Law of Thermodynamics – conservation of energy
- ?U = W + Q
- W = - (area bounded by the PV graph and the x-axis)
- Expansion of a gas is negative work done since the internal energy of the gas is reduced unless heat is added
- Compression of the gas by an external agent is positive work
- Four gas processes – isothermal, adiabatic, isobaric, and isovolumetric LAB – PV measurements of a confined gas
- 1st Law “zero” conditions for isothermal, adiabatic, and isovolumetric
- PV diagrams
- State variables: P, V, U, T, and S (moving from an initial position’s values to a final position’s values)
- Understand when heat will be added or removed during compressions/expansions of each type
- Closed cycles VIDEO DISCUSSION – Discovery of Energy/Heat
- Clockwise cycles define net Work as negative
- VIDEO DISCUSSION – James Watt and the Steam Engine
- U equals zero
- Qnet = -Wnet
- Efficiency formulas eff = W/Qin = 1 – (Qout/Qin)
- Qin = Qout + W
- Carnot Cycle and ideal efficiency
- 2nd Law of Thermodynamics
- If an isolated system undergoes spontaneous change there is an increase in the disorder of the system
- S = Q/T S = k ln(O) Suniverse = 0
- Entropy is a statistical, macro measurement of a system’s disorder – not reversible without doing work on the system
- 3rd Law of Thermodynamics
- Absolute Zero cannot be reached in a finite number of steps (it is a mathematical limit, not an attainable temperature)
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