Thermodynamic Processes and The First Law

Chapter 13: Temperature and kinetic Theory - a related concept used in this section

Boyle's Law: If keep T constant, then V inversely proportional to P or, equivalently PV = constant

Some Definitions - We are considering ideal gasses

 

ð Isothermal process           One that is carried out at constant temperature         T = constant, DU = 0, Q = W   ð Isotherms           PV diagram curves drawn at constant temperature (Figure 1 on right)   ð Adiabatic process           One in which no heat is allowed to flow into or out of the system (Q = 0).
	1. Isothermal Process	2. Isothermal - Adiabatic Processes

ð Heat Reservoir

A body whose mass is so large that, idealy, its temperature does not change significantly when heat is exchanged with a system

 

 

ð Isobaric process One in which the pressure is kept constant   ð Isovolumetric or isochoric process One in which the volume does not change

 

 

 

If pressure is kept constant (curve a on the right) W = Fd = PAd = PDV So, the work is the area under the PV curve bounded as shown If the pressure is not kept constant (curve b on the right) W is still the area under the curve, bounded as shown, obtainable using calculus or some approximation technique