Flashcards in Module 2-2 Deck (33):

1

## What is moving boundary work

### PdV work. work caused by moving the boundary of the system in a CM system

2

## When is moving boundary work not applicable

### Rigid systems (inflexible boundaries)

3

## what is the difference between point functions and path functions

### With a point function, knowing the end of the points is enough to determine the value of the integral. With path functions we need the entire path to determine the total amount added

4

## What are common path vs point functions

###
Energy -> point function

Work -> path function

Heat -> Path function

(W2, Q2, W1, Q1 are meaningless)

5

## What are thermodynamic properties

###
Properties related to energy

(P,v,T,u,h,s)

6

## What determines the number of independent thermo properties

### # of independent TD properties = (# of reversible work modes) + 1

7

## What is a simple compressible substance

### substance where the only reversible work mode is PdV work

8

## How many idep TD properties are there for a SCS

### 2 (1 reversible work mode + 1 for heat transfer)

9

## What is a compressed liquid

### At a given P, the T is too low to vaporize. Additional Q increases T

10

## What is a saturated liquid

### At a given P, the T at which adding any more Q will lead to vaporization

11

## What is a saturated mixture

### At a given P, T is at the phase change T. Both phases exist, adding Q increases the amount of vapor

12

## What is a saturated vapor

### at a given P, the T is such that removing Q will lead to condensation

13

## what is a superheated vapor

### at a given P, T is high enough that removing Q will not lead to condensation

14

## What is the vapor dome?

### The two phase region. In the region, Lines of constant temperature are horizontal (constant P)

15

## What is the critical point

### The top of the vapor dome. At this pressure/temp combo, there is no observable phase change from liquid->vapor

16

## What is a saturated mixture

### mixture of states in the vapor dome

17

## what is the mixture quality?

### x = mg/m (percent that is gas)

18

## What is the mixture quality of a saturated liquid

### 0

19

## what is the mixture quality of a saturated vapor

### 1

20

## How do we determine TD properties within the vapor dome

### y = (1-x)y_liquid + x*y_vapor

21

## how can we determine the mixture quality from a property, y?

###
x = (y-yf)/(yg-yf) =

22

## What is enthalpy?

### h = u + Pv, H= U + PV

23

## how is u defined

### u is defined from a reference point. Due to this, we are unable to mix tables and figures as they have different reference points

24

## For a SCS, most TD properties are function of what other property

### Most properties are a function of temperature alone (v,u,h,s) (although h is slightly affected by p)

25

## what are the two ways of calculating h for a SCS?

###
h = u(Tsat) + P*v(Tsat),

h = h(Tsat) + v(Tsat)*(P-Psat)

26

## What is the ideal gas state equation

### Pv = RT

27

## What is the compressibility factor and how is it used?

### Z = Pv/RT. When Z is close to 1 the ideal gas law holds

28

## What limitations are there for when we can assume ideal gas?

### P << Pcr or T > 2*Tcr

29

## What is specific heat?

### the amount of energy required to raise the temperature 1K per unit mass

30

## What are the euqations for specific heat

###
cv = dU/dT at constant v

cp = dh/dT at constant P.

Note: v or p do not need to be constant in order to use cv and cp

31

## how does internal energy vary for an ideal gas

### internal energy is only dependent on temperature. u = u(T)

32

## how does enthalpy vary for an ideal gas

### enthalpy is a function of u + Pv, but Pv = RT. therefore h = u(T) + RT, it is a function of T alone

33