Ideal Gas

• Concept: What is an ideal gas?
• Equation of state: The ideal gas law, PV = nRT, or PV = NkT (you do not have to remember the values of the constants R and k).
• Avogadro's number: The number of particles in a mole of ideal gas, N_A = 6.02 10²³.

Kinetic Theory

• Concept: What is kinetic theory?
• Main equation: Mean kinetic energy of a particle in an ideal gas, mv²_mean/2 = (3/2) kT.

First Law of Thermodynamics

• Concept: What is thermodynamics?
• Statement: Change in internal energy E_system = Q + W, where Q is the heat transferred to the system, and W the work done on the system (by non-conservative forces).
• Work: Work done on a system with constant pressure W = –P V.

Second Law of Thermodynamics

• Idea: In order to perform work, energy must flow between two reservoirs set at different temperatures. By itself, heat always flows from warmer to colder objects. The flow introduces disorder into the system. Irreversible processes.
• Statements: In terms of direction of heat flow, and change in entropy; Interpretation in terms of disorder and "organized energy".
• Entropy: For an object at temperature T that absorbs heat Q, S = Q/T.