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Flashcards in THERMO6 Deck (24):
1

State Variables

-P, V, T, Eint are state variables
-this means that once a point is marked on a P-V diagram (for a fixed sample) defines all of these variables

2

Are Q and W state variables?

No, they are a measure of energy that flows into/out of a system and depend on the route taken between points on a PV diagram rather than the positions of the points themselves

3

Equations that always true for both real gases

ΔEint = Qin + Won
Won = -∫P dv

4

Equations that are always true for ideal gases

ΔEint = Qin + Won
Won = -∫P dv
PV = nRT
ΔEint = CvΔT
Eint = DoF*n*1/2 RT

5

Isobaric Process
Definition

ΔP = 0
e.g. experiment is open to the atmosphere

6

Isochoric Process
Definition

ΔV = 0
e.g. experiment takes place in a rigid container

7

Isothermal Process
Definition

ΔT = 0
a slow process to allow heat to flow in or out of the system to maintain temperature
all energy entering the system is used to do work rather than to increase the internal energy

8

Adiabatic Process
Definition

Qin = 0
e.g. insulated processes
-usually have to be very rapid to prevent any flow of energy into or out of the system

9

Isobaric Process
Won

Won = -PΔV

10

Isobaric Process
Qin

Qin = ΔEint - Won = CvΔT + PΔV

11

Isobaric Process
ΔEint

ΔEint = CvΔT

12

Isochoric Process
Won

Won = 0

13

Isochoric Process
Qin

Qin = ΔEint

14

Isochoric Process
ΔEint

ΔEint = CvΔT

15

Isothermal Process
Won

Won = nRT ln(Vi/Vf)

16

Isothermal Process
Qin

Qin = -Won

17

Isothermal Process
ΔEint

ΔEint = 0

18

Adiabatic Process
Won

Won = Cv/nR (PfVf - PiVi) = 1/(1/γ) (PfVf - PiVi)

19

Adiabatic Process
Qin

Qin = 0

20

Adiabatic Process
ΔEint

ΔEint = CvΔT

21

Work Done in a Cycle

the area enclosed by the shape on a P-V diagram

22

Work Done on a Gas

area under the line on a PV diagram i.e.
Won = - (Vi->Vf) ∫P dv

23

Adiabatic Process
P, V & T

-in an adiabatic process V, P and T can all change
PV^γ = constant
TV^(γ-1) = constant
PV = nRT (for an ideal gas)

24

Internal Energy of an Ideal Gas

ΔEint = CvΔT