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Thermodinamica > Lecture 2 - Terminology & Equations > Flashcards

Lecture 2 - Terminology & Equations Flashcards

1
Q

The first law of thermodynamics is also known as …

A

the conservation of energy law.

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2
Q

Thermodynamics is a science that deals with _______.

A

energy

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3
Q

The first law of thermodynamics for a closed system as an equation is __________, where ___________, and the units are in ___________.

A

Q – W = ∆E (for a closed system)
Q = heat transfer
W = Work
∆E = change in energy

Joules

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4
Q

Heat flow into a system is considered _______.

A

Positive

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5
Q

Heat flow out of a system is considered _______.

A

Negative

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6
Q

Work done by the system is considered _________.

A

positive

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7
Q

Work done on a system is considered _________.

A

negative

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8
Q

∆E is the sum of _________, where ___________.

A

∆U, ∆KE, and ∆PE
where ∆U is the change in internal energy of the matter of the system we are considering
∆KE is the change in kinetic energy, which is the macroscopic motion of the system
∆PE is the change in potential energy, which is the change in height of the system

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9
Q

∆U is the change in ____________ of the matter of the system we are considering in the form of __________, __________, or _____________ for a solid.

A

internal energy
molecular motion
lattice vibration
electron motion

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10
Q

∆KE is the ____________, which is like _________, even though it is the molecules themselves that are moving around.

A

macroscopic motion of the system

a big chunk of a system that moves together at the same velocity

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11
Q

∆PE is _____________ or the change in height of a system.

A

the change in elevation with respect to some reference frame.

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12
Q

∆E = ___ + _____+ ________ [_]

A

∆U + ∆KE + ∆PE [J]

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13
Q

The second law of thermodynamics helps us …

A

helps us figure out which direction the energy is flowing within a system

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14
Q

The second law of thermodynamics ______________ in which a __________ and __________ is.

A

determines the direction

how efficiently that process

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15
Q

The two types of systems in thermodynamics are _______ and ___________.

A

open system

closed system

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16
Q

A closed system is also called a _____________ because ______________.

A

fixed mass system

mass can’t cross the boundary of the system

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17
Q

A closed system can be defined as _____________.

A

A system of fixed mass

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18
Q

A piston (pistón o émbolo) cylinder device with a load on top and a gas within the cylinder with a _________ boundary ___________ of the cylinder is an example of a ______________ system.

A

checkered line
along the lines
closed system

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19
Q

In a closed system, everything ____________ is the surroundings

A

outside the system

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20
Q

In a closed system, the few things that can cross the system boundary are found in _____________ and are _____ and ___________.

A

the first law of thermodynamics
heat
work

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21
Q

In a closed system, ___________ and ______________ both move _____________.

A

heat
work
into and out of the system

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22
Q

A propeller (hélice o propulsor) rotating in a cylinder with a load on top is an example of a ___________, and the propeller produces ____________, which _____________ inside the cylinder.

A

closed system
shaft work
heats up the gas

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23
Q

In the process of heating up a gas, we are doing ______.

A

work

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24
Q

In a closed system, work and heat cross the system boundary but mass can’t, which is why a closed system is a fixed mass system.

A

True

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25
Q

In an open system, ______________.

A

mass can cross the boundary of a system

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26
Q

An open system can be described as ______________.

A

a system that involves mass transfer across its boundary

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27
Q

A turbine (turbina), compressor (compresor), or pump (bomba, surtidor, pompa) are examples of an _____________ system.

A

open

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28
Q

Piston in spanish

A

pistón o émbolo

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29
Q

Turbine in spanish

A

turbina

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30
Q

Compressor in spanish

A

compresor

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31
Q

Pump in spanish

A

bomba, surtidor o pompa

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32
Q

Pump in spanish

A

bomba, surtidor o pompa

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33
Q

Jet in spanish

A

surtidor

34
Q

The boundary of an open system is called ____________ because ____________.

A

the control surface

mass can cross the boundary

35
Q

Within the control surface, we have ___________.

A

a control volume

36
Q

In an open system, ____________.

A

mass flows in and out

37
Q

When doing an analysis of an open system, we have to describe __________________.

A

the conditions of the fluid moving into and out of the system.

38
Q

In an open system, we describe the _______, ____________, and ___________ going into a system.

A

pressure, P1
temperature, T1
velocity, v1

39
Q

In an open system, we describe the ____, ________, ___________ leaving the system.

A

pressure, P2
temperature, T2
velocity, v2

40
Q

Q and W flow ___________ a control surface.

A

across

41
Q

Ẇ is the __________ in __________ or ______.

A

rate of work produced
[J/s]
[W]

42
Q

Q̇ is the ___________ in __________ or _________.

A

rate of heat transfer per unit time
[J/s]
[W]

43
Q

Properties describe the state of a system.

A

True

44
Q

The three types of properties are __________.

A

extensive
intensive
specific

45
Q

Extensive properties are __________, and all the symbols are _____________, except for _________. Examples are ____________.

A

dependent on the mass or size of the system

all in capital letters

mass

mass (m), volume (V), and total energy (E)

46
Q

Intensive properties are _____________. Examples are __________.

A

not dependent on the size of the system

temperature (T), and pressure (P)

47
Q

Specific properties are _____________, and their symbols are ______. For example _____________.

A

extensive properties per unit mass
in small letters
specific volume (v), specific total energy (e), and specific internal energy (u)

48
Q

u =
e =
v =

A

U/m
E/m
V/m

49
Q

In thermodynamics, the letter “v” smybolizes

A

volume

50
Q

A __________ describes the state of a system.

A

property

51
Q

A _________ is described by its properties.

A

system

52
Q

Properties are _____________ to which __________ without ____________.

A

macroscopic characteristics
numerical values are assigned
previous knowledge of the history of the system

53
Q

The origins of properties are _____________, like _____________, ________________ , like entropy, or ___________, like enthalpy.

A
  1. directly measured, like pressure and temperature
  2. Defined by the laws of thermodynamics
  3. defined by mathematical combinations
54
Q

Enthalpy = (U+P)*v

A

True

55
Q

The state of a system, is a description of _________________ from a small subset of __________.

A

the condition of the system at a given instant

independent property values

56
Q

From a number of property values, we can specify the state in which a system currently is.

A

True

57
Q

Once we have specified the state of the system from ____________, usually ____, all other properties properties ___________ or determined from the subset.

A

a small number of independent property values
2
have been defined

58
Q

Equilibrium in thermodynamic systems are described as ______________.

A

being in a state of equilibrium

59
Q

Properties are only defined when ______________, so no unbalanced potentials or __________ are within the system.

A

they are in a state of equilibrium

driving forces

60
Q

For a system in equilibrium, there is no temperature or pressure difference.

A

True

61
Q

A process is _____________.

A

the transformation of a system from 1 state to another

62
Q

End states are the beginning and final state of a process.

A

True

63
Q

We use a process diagram to know where we are within different properties or states.

A

True

64
Q

A dot or circle with a number next to it in a process diagram represents the _________.

A

end state

65
Q

In a process diagram, we include _______.

A
  1. the end states
  2. the direction of the process, indicated by an arrow
  3. the process path
66
Q

The direction of a process is indicated by an arrow.

A

True

67
Q

The process path is the line connecting two end points.

A

True

68
Q

A complete description of a process requires:

A
  1. specification of the end states
  2. the process path
  3. the interactions across the boundaries
69
Q

The process path tells us which way a process is going and which properties it goes through from 1 end point to another.

A

True

70
Q

Examples of the interactions across the system boundaries are ______________.

A

heat, work, and mass (in an open system)

71
Q

When a system undergoes a change of state, the change ______________ does not depend on the process connecting two end states.

A

in the value of the properties

72
Q

When a system undergoes a change of state, the change in the value of the properties does not depend on the process connecting two end states. This means that ___________.

A

going through any state path, the pressure or volume won’t change, for example, but the work, heat, or mass (if in an open system) will.

73
Q

When a system undergoes a change of state, the change in value of a property ____________.

A

does not depend on the process connecting the two end states

74
Q

If we have a value that does depend on the process path between two end states, _____________.

A

that quantity is not a property

75
Q

If the value of a quantity depends on the nature of the process between the two end states, that quantity is not a property. For example, _______________.

A

heat, work, and mass

76
Q

Cycles are _____________ (path has the same end state).

A

A process where the process path has identical end states

77
Q

Systems that we study are not really in equilibrium, so we make an approximation in the modelling of the system.

A

True

78
Q

A quasi-equilibrium process ___________

A

assumes that the system remains close to its equilibrium state during the process.

79
Q

Quasi - equilibrium is an ___________ because very few real processes are in quasi-equilibrium.

A

idealization

80
Q

Quasi-equilibrium process is the standard with which we compare real world processes.

A

True

81
Q

Work-producing devices produce maximum work in the quasi-equilibrium state, and real world systems are a little under the quasi-equilibrium state.

A

True

Thermodinamica (10 decks)

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