KINDS OF THERMODYNAMIC PROCESSES ADIABATIC – NO HEAT TRANSFER; Q = 0; U = -W ISOCHORIC – CONSTANT VOLUME; U = Q ISOBARIC – CONSTANT PRESSURE; W = p (V 2 – V 1 ) ISOTHERMAL – CONSTANT TEMPERATURE; only for ideal gas U = 0, Q = W The First Law of Thermodynamics Q = U + W or U = Q - W
Fig. 17-13 Processes for an ideal gas: adiabatic Q=0 isochoric W=0 isothermal U=0
Fig. 17-14 The internal energy of an ideal gas depends only on its temperature, not on its pressure of volume.
Fig. 17-15 Raising the temperature of an ideal gas by various processes Q = U + W and U = f(T) Isochoric W=0 so Q= U Isobaric Q = U + p(V 2 -V 1 )