thermo chapter 2

Question 1

conservation of the
quality of energy, not the quantity

Answer 1

Energy Conservation

Question 2

which is of the highest quality of energy, for
example, can always be converted to an equal amount of
thermal energy (also called heat).

Answer 2

Electricity,

Question 3

Energy can exist in numerous
forms such as thermal,
mechanical, kinetic, potential,
electric, magnetic, chemical,
and nuclear, and their sum
constitutes the

Answer 3

total energy E

Question 4

Thermodynamics provides no
information about the absolute
value of the total energy. It deals
only with the

Answer 4

change of the total
energy,

Question 5

of energy
are those a system possesses
as a whole with respect to some
outside reference frame, such as

kinetic and potential energies

Answer 5

macroscopic forms

Question 6

of energy are those
related to the molecular structure of a system
and the degree of the molecular activity, and
they are independent of outside reference
frame

Answer 6

microscopic forms

Question 7

The sum of all the
microscopic forms of energy. Denoted by U

Answer 7

internal energy

Question 8

energy that a system
possesses as a result of its motion relative

to some reference frame

Answer 8

kinetic energy (KE)

Question 9

the energy that a
system possesses as a result of its elevation
in a gravitational field

Answer 9

potential energy (PE)

Question 9

The magnetic, electric, and surface tension effects are
significant in some specialized cases only and are usually
ignored

Answer 9

total energy of a system

Question 9

closed systems whose velocity and elevation of the center of gravity remains constant during a process are often referred to as

Answer 9

stationary systems

Question 10

the amount of mass flowing through a cross section

Answer 10

mass flow rate

Question 11

which is the volume of a fluid flowing through a cross section per unit time

Answer 11

volume flow rate

Question 12

• the form of
  energy that can be converted to
  mechanical work completely and
  directly by an ideal mechanical
  device such as an ideal turbine

Answer 12

Mechanical Energy

Question 13

Kinetic and potential energies are the
familiar forms of

Answer 13

mechanical energy.

Question 14

the pressure of a flowing fluid is also associated with its
mechanical energy pressure unit Pa is equivalent to

Answer 14

Mechanical Energy

Question 15

pressure itself is not a form of energy, but a
pressure force acting on a fluid through a distance
produces work,

Answer 15

flow work,

Question 16

Energy can cross the boundary of a
closed system in two distinct forms:

Answer 16

heat and work

Question 17

is defined as the form of
energy that is transferred between
two systems (or a system and its
surroundings) by virtue of a
temperature difference

Answer 17

Heat

Question 18

is energy in transition. It is
recognized only as it crosses the
boundary of a system

Answer 18

Heat

Question 19

A process during which there is no
heat transfer is called

Answer 19

adiabatic
process

Question 20

Heat transfer per unit mass of a system is denoted

Answer 20

q

Question 21

the amount of heat being transferred per unit time

Answer 21

rate of the heat transfer

Question 22

heat transfer is denoted by

Answer 22

.Q

Question 23

it is also a form of energy that is being transferred by heat

Answer 23

work

Question 24

have inexact differentials designated by the symbol δ. differential amount of heat or work is represented by δQ or δW, respectively, instead of dQ or dW

Answer 24

Path functions

Question 25

For a specified constant torque, the work done during n revolutions is determined as follows: A force F acting through a moment arm r generates a torque T of

Answer 25

SHAFT WORK

Question 25

are point functions (i.e., they depend on the state only, and not on how a system reaches that state), and they have exact differentials designated by the symbol d. A small change in volume, for example, is represented by dV, and the total volume change during a process between states 1 and 2 is

Answer 25

Properties

Question 25

The net change (increase or decrease) in the total energy of the system during a process is equal to the difference between the total energy entering and the total energy leaving the system during that process

Answer 25

ENERGY BALANCE

Question 26

The determination of the energy change of a system during a process involves the evaluation of the energy of the system at the beginning and at the end of the process, and taking their difference

Answer 26

ENERGY CHANGE OF A SYSTEM

Question 27

Heat transfer to a system (heat gain) increases the energy of the molecules and thus the internal energy of the system

Answer 27

Heat Transfer, Q

Question 28

An energy interaction that is not caused by a temperature difference between a system and its surroundings is work

Answer 28

Work Transfer, W

Question 29

Mass flow in and out of the system serves as an additional mechanism of energy transfer. When mass enters a system, the energy of the system increases because mass carries energy with it

Answer 29

Mass Flow, m

Question 30

is defined as the ratio of the energy delivered to the house by hot water to the energy supplied to the water heater

Answer 30

efficiency of a water heater

Question 31

which is the ratio of the electrical power output to the mechanical power input

Answer 31

Generator efficiency

Question 32

is usually defined as the ratio of the net shaft work output of the turbine to the heat input to the working fluid

Answer 32

thermal efficiency of a power plant

Question 33

as the ratio of the net electrical power output to the rate of fuel energy input

Answer 33

overall efficiency for the power plant

Question 34

defined as the amount of light output in lumens per W of electricity consumed

Answer 34

lighting efficacy

Question 35

can be defined as the ratio of the useful energy transferred to the food to the energy consumed by the appliance

Answer 35

efficiency of a cooking appliance