chapter19 - Thermodynamic systems Isolated systems can...

Info iconThis preview shows pages 1–10. Sign up to view the full content.

View Full Document Right Arrow Icon
Isolated systems can exchange neither energy nor matter with the environment. Closed systems exchange energy but not matter with the environment. Heat Work reservoir Open systems can exchange both matter and energy with the environment. Heat Work reservoir Thermodynamic systems
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Quasi-static processes : near equilibrium Initial state, final state, intermediate state: p, V & T well defined Sufficiently slow processes = any intermediate state can considered as at thermal equilibrium. Thermal equilibrium means that It makes sense to define a temperature. Examples of quasi-static processes: - isothermal: T = constant - isochoric: V = constant - isobaric: P = constant - adiabatic: Q = 0 Quasi-static processes
Background image of page 2
Work in thermodynamics Expansion: work on piston positive, work on gas negative Compression: work on piston negative, work on gas positive
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Work during a volume change = = = = 2 1 . . V V pdV W pdV Adx p dx F dW
Background image of page 4
Work in pV diagrams Work done equals area under curve in pV diagram Careful with the signs…
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
1 st Law of Thermodynamics W Q U - = Conservation of energy Heat is positive when it enters the system Work is positive when it is done by the system Heat is negative when it leaves the system Work is negative when it is done on the system
Background image of page 6
1 st Law of Thermodynamics pdV dQ dU - = Conservation of energy Heat is positive when it enters the system Work is positive when it is done by the system Heat is negative when it leaves the system Work is negative when it is done on the system
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
) ( 1 2 2 V V p W - = a. isochoric b. isobaric a. isobaric b. isochoric ) ( 1 2 1 V V p W - = = f i V V pdV W isothermal The work done by a system depends on the initial and final states and on the path b it is not a state function. • Amount of heat transferred also depends on the initial, final, and intermediate states b it is not a state function either. (a) (b) (c) State Functions
Background image of page 8
1 2 U U W Q U - = - = The internal energy U is a state function: the energy gain (loss) only depends on the initial and final states, and not on the path. Even though
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 10
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 30

chapter19 - Thermodynamic systems Isolated systems can...

This preview shows document pages 1 - 10. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online