Definitions and E Balance

Question 1

A ____ system has no mass exchange

Answer 1

Closed

Question 2

A open system that has mass exchanged is studied by looking at a…

Answer 2

Control Volume

Question 3

Are boundaries fixed?

Answer 3

No, they may move or change shape/size over time

Question 4

A ___ system has no mass exchange and no ____

Answer 4

Isolated, energy

Question 5

A process is a transformation from one state…

Answer 5

to another state

Question 6

A property is a __________ of a system that desciribes its ____

Answer 6

macroscopic characteristic, condition

Question 7

An intensive property is

Answer 7

size INDEPENDENT

Question 8

an Extensive property is

Answer 8

size DEPENDENT

Question 9

_____ is a condition of a system at a given time described by it’s properties

Answer 9

STATE

Question 10

A State is called “fixed” if….

Answer 10

a minimum number of properties known to describe it completely

Question 11

Energy is a ____ property

Answer 11

extensive

Question 12

Some examples of intensive properties

Answer 12

Temperature, Pressure, density, molar mass

Question 13

True or false: there may be infinitely many process paths between any 2 given states

Answer 13

TRUE

Question 14

at ___ state, the system condition does not change with time

Answer 14

steady

Question 15

_____ is the lowest energy state possible, where the system usually is at ____

Answer 15

DEAD STATE, equilibrium with its surroundings

Question 16

An equilibrium is ….

Answer 16

the balance of an influence (ex mechanical, chemical, phase)

Question 17

Thermodynamic Equilibrium means….

Answer 17

all influences on a system are in balance at the same time

Question 18

Quasi-equilibrium state means…

Answer 18

system is very close to equilibrium, it’s a very slow process, completed in a piece wise equilibrium

Question 19

____ is energy in transit

Answer 19

Work

Question 20

Equation for work (mechanical)

Answer 20

W = integral{Ft * ds}

Question 21

2nd law

Answer 21

entropy naturally increases; restoring order requires effort

Question 22

Work is = 0 if there is no ____ in the direction of the force applied at the boundary

Answer 22

displacement

Question 23

Power = F_vector *…

Answer 23

(dot product) w/ velocity vector

Question 24

Work is _____ energy transit

Answer 24

path dependent

Question 25

Change in stored system energy is ____

Answer 25

path independent

Question 26

Equation for Work done by a gas through volume expansion under pressure

Answer 26

W = integral{p * dv}

Question 27

Equation for Work (electric)

Answer 27

Integral { V(t)*I(t)*dt}

Question 28

Work_dot (electric) = Power =

Answer 28

I*V

Question 29

0th law

Answer 29

When two objects at different temperatures, energy flows from warmer to colder in the form of heat until they reach thermal equilibrium (same temperature)

Question 30

Work is ____ valuable form of energy transfer than heat

Answer 30

More

Question 31

These 2 types of heat interaction rely on physical contact

Answer 31

convection and conduction

Question 32

____ is the dominant mode of heat transfer in solids

Answer 32

conduction

Question 33

Internal energy is tied to the ____ of a system

Answer 33

temperature

Question 34

for an incompressible substance, c_p =

Answer 34

c_v = c

Question 35

delta U of an ideal gas =

Answer 35

m*c_v*deltaT

Question 36

The 1st law states

Answer 36

energy is conserved

Question 37

A reversible process is ______ concept

Answer 37

an ideal

Question 38

Irreversibilities may be ____ and/or ____

Answer 38

internal; external

Question 39

A thermal reservoir is....

Answer 39

a body at constant temp while its energy changes; ideal object

Question 40

A polytropic process is described by

Answer 40

p*V^n = constant

Question 41

A quasi-static process is...

Answer 41

a process that happens infinitely slowly

Question 42

A quasi equilibrium process is...

Answer 42

a quasi-static process in which the system is always in equilibrium (ie. slow expansion or compression)

Question 43

For expansion and contraction of gases, Work =

Answer 43

area under PV curve

Question 44

change in total E for a cycle =

Answer 44

0

Question 45

For a cycle, average rate of E_in =

Answer 45

average rate of E_out

Question 46

Delta (any property) = 0 for

Answer 46

a cycle

Question 47

A power cycle...

Answer 47

converts heat to work

Question 48

Examples of irreversibilities

Answer 48

electrical resistance; friction; mixing of liquids or vapors, plastic deformation

Question 49

Efficiency of a power cycle =

Answer 49

W_net out/Q_heat in from warm reservoir

Question 50

COP_Refrig =

Answer 50

QL/W_net in

Question 51

COP_heat

Answer 51

QH/W_net in

Question 52

Is the reverse of the Kelvin Plank statement true?

Answer 52

Yes

Question 53

Can carnot efficiencies be applied to individual processes?

Answer 53

No, only cycles

Question 54

If the SCI = 0 then system is

Answer 54

internally reversible

Question 55

An impossible system has an SCI ...

Answer 55

< 0

Question 56

SCI gives a measure of ...

Answer 56

irreversibilities and relative inefficiencies

Question 57

Units of entropy

Answer 57

kJ / K

Question 58

Entropy production is a measurement of...

Answer 58

the irreversibilties in a given process

Question 59

Can sigma_p < 0 ?

Answer 59

NO

Question 60

If there is heat flow out of your system, system entropy should

Answer 60

decrease

Question 61

Can SCI be applied to individual processes?

Answer 61

NO

Question 62

Is entropy conserved?

Answer 62

NO

Question 63

Can entropy balance be applied to processes?

Answer 63

YES