Chapter 4 Flashcards

1
Q

The expansion and compression work in a piston-cylinder device

A

Moving boundary work (P dV work)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

A process during which the system remains nearly in equilibrium at all times

A

Quasi-equilibrium process

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Wb is positive for ____

A

Expansion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Wb is negative for ____

A

Compression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

The work associated with a moving boundary is called _____

A

Boundary work

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

The boundary work done during a process depends…

A

On the path followed as well as the end states

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

The area under the process curve on a P-V diagram represents the _____

A

Boundary work

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

The area under the process curve on a P-V diagram is equal, in magnitude, to…

A

The work done during a quasi-equilibrium expansion or compression process of a closed system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

The net work done during a cycle

A

The difference between the work done by the system and the work done on the system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the boundary work for a constant volume process?

A

Wb=0

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Boundary work done during _____ is always zero

A

A constant volume process

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Energy balance when sign convention is used

A

Heat input and work output are positive

Heat output and work input are menegative

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Stationary system: energy balance

A

Q-W = change in U

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Work done on the system

A

Negative

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Work done by the system

A

Positive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Closed system undergoing a quasi-equilibrium process

A

P = constant process energy balance

Not valid for closed systems processes

17
Q

Expansion against a vacuum

A

Involves no work and no energy transfer

18
Q

The energy required to raise the temperature of the unit mass of a substance by one degree as the volume is maintained constant

A

Specific heat at constant volume (cv)

19
Q

The energy required to raise the temperature of the unit mass of a substance by one degree as the pressure is maintained constant

A

Specific heat at constant pressure (cp)

20
Q

The specific heat of a substance changes with _____

A

Temperature

21
Q

Cv and Cp are ____

A

Properties

22
Q

The change in internal energy with temperature at constant volume

23
Q

The change in enthalpy with temperature at constant pressure

24
Q

Cp is always greater than Cv. True or False?

25
At low pressures, all real gases approach behavior, and therefore their specific heats depend on ____ only
Temperature
26
The specific heats of real gases at low pressures are called ____
Ideal gas specific heats, zero-pressure specific heats (Cp0, Cv0)
27
Specific heat ratios of monatomic gases
It’s value is essentially constant at 1.667
28
Specific heat ratios for diatomic gases
1.4 at room temperature
29
Specific heat ratio varies with _____
Temperature
30
A substance whose specific volume (or density) is constant
Incompressible substance Solids and liquids Cv=Cp Specific volumes remain constant
31
Liquids at constant pressure
Heaters
32
Liquids at constant temperature
Pumps