


Heat necessary for phase change
 L is the latent heat of the phase change



Heat transfer rate
 k is the thermal conductivity, A is crosssct area, L is length, T is temp. difference between two sides

Ideal gas law
 KELVINS


average kinetic energy of ideal gas
 KELVINS

rootmeansquare speed
 KELVINS
 M is molar mass (in kg), mu is molecular mass


Ideal gas at STP
22.4 L at 1 atm and 273 K

Zeroth law of thermodynamics
 Transitive property of thermal equilibrium
 Heat flow = 0 in closed systems

Work done by ideal gas (heat must be removed)
 Positive when work is done on system, negative when system does work

Work when pressure changes
 Area under PV curve
 Increasing volume gives negative work, decreasing volume gives positive work

First law of thermo
 No phase changes.
 For constant volume, W=0 and

Isochoric process
 No change in volume
 Change in internal energy due entirely to heat transfer

Isothermal process
No temperature changes


Efficiency of heat engines
 Q_H is heat energy discarded

Carnot cycle
1. Isothermal expansion (absorbs heat from highenergy source and expands; because temp doesn't increase, all heat goes into work performed by expanding gas)
2. Adiabatic expansion (system expands w/o exchanging heat w/ surroundings; it thus does negative work, so its internal energy and temperature decrease)
3. Isothermal compression  environment does work on gas, and it discards heat to lowtemperature reservoir rather than increasing internal energy
4. Adiabatic compression  system compressed to initial state with no heat exchange, so its internal energy and temp increase

Carnot efficiency
 KELVINS

