Topic 2

Question 1

Kinetic energy is

Answer 1

Scalar Quantity

Question 2

What is an extensive property?

Answer 2

An extensive property is one that depends on the amount of matter in a system or the size of the system

Question 3

Why is kinetic energy an extensive property?

Answer 3

it changes in proportion to the amount of matter in a system

Question 4

What is the difference between a scalar and a vector quantity?

Answer 4

A scalar quantity has only magnitude, but no direction. Vector quantity has both magnitude and direction

Question 5

Why is potential energy also considered an extensive property?

Answer 5

Because it depends on the amount of matter in the system—in other words, it scales with the size or quantity of the system.

Question 6

Work is equal to

Answer 6

Force (distance)

Question 7

Conversation of Energy

Answer 7

states that the total work of all forces acting on the body from the surroundings, with the exception of the gravitational force, equals the sum of the changes in the kinetic and potential energies of the body.

Question 8

Thermodynamic definition of work

Answer 8

“Work is done by a system on its surroundings if the sole effect
on everything external to the system could have been the
raising of a weight.

Question 9

W > 0

Answer 9

positive (+)

Question 10

W < 0:

Answer 10

negative (-)

Question 11

work done BY the system

Answer 11

positive (+)

Question 12

work done ON the system

Answer 12

negative (-)

Question 13

The rate of energy transfer by work

Answer 13

Power

Question 14

is one in which the departure from thermodynamic equilibrium is at most infinitesimal.

Answer 14

quasiequilibrium process (or quasistatic) process

Question 15

a change that a gas undergoes under general conditions

Answer 15

Polytropic Process

Question 16

When n = 0 in a polytropic process

Answer 16

process is an isobaric (constant-pressure) process

Question 17

When n = +- infinity in a polytropic process

Answer 17

process is an isometric (constant-volume) process

Question 18

For ideal gas n = 1 in a polytropic process

Answer 18

isothermal (constant-temperature) process

Question 19

Internal energy is what property

Answer 19

extensive property of the system

Question 20

amount of energy transferred across the boundary of a system in a heat interaction with the system’s surroundings.

Answer 20

Heat

Question 21

Q > 0

Answer 21

positive (+)

Question 22

Q < 0

Answer 22

negative (-)

Question 23

heat transfer from the system

Answer 23

negative (-)

Question 24

heat transfer to the system

Answer 24

positive (+)

Question 25

Work and Heat is a property?

Answer 25

Both are not a property

Question 26

lowercase delta (δ)

Answer 26

denotes an infinitesimal or differential amount of heat added to or removed from a system. This symbol highlights that heat (𝑄) is a path-dependent quantity, meaning it depends on the specific path taken during a process rather than the end states alone.

Question 27

units for heat transfer Q and heat transfer rate Q (.)

Answer 27

same as those introduced previously for W and W (.) respectively.

Question 27

adiabatic

Answer 27

means without heat transfer.

Question 28

if a system undergoes a process involving no heat transfer with its surroundings

Answer 28

adiabatic process

Question 29

Heat Transfer Modes

Answer 29

Three basic transfer mechanisms: 1. Conduction 2. Convection 3. Thermal radiation

Question 30

Energy transfer can take place in solids, liquids, and gases.

Answer 30

Conduction

Question 31

Transfer of energy from the more energetic particles of a substance to adjacent particles that are less energetic due to interactions between particles.

Answer 31

Conduction

Question 32

rate of heat transfer across any plane normal to the x direction, Qx, is proportional to the wall area, A, and the temperature gradient in the x direction, dT/dx:

Answer 32

Fourier’s law

Question 33

the negative gradient of temperature and the time rate of heat transfer is proportional to the area at right angles of that gradient through which the heat flows

Answer 33

Fourier’s law

Question 34

Fourier’s law is also known as

Answer 34

law of heat conduction

Question 35

Substances with large values of thermal conductivity

Answer 35

good conductors

Question 36

Substances with small values of thermal conductivity

Answer 36

good insulators

Question 37

is emitted by matter as a result of changes in the electronic configurations of the atoms or molecules within it.

Answer 37

Thermal radiation

Question 38

The energy is transported by

Answer 38

electromagnetic waves (or photons)

Question 39

requires no intervening medium

Answer 39

thermal radiation

Question 40

Stefan–Boltzmann law

Answer 40

shows that the thermal radiation is associated with the fourth power of the absolute temperature of the surface, Tb

Question 41

Stefan–Boltzmann law states that

Answer 41

the magnitude of the radiation output of an object is directly proportional to the fourth power of its surface temperature

Question 42

property of the surface that indicates how effectively the surface radiates (0≤ ε ≤ 1.0)

Answer 42

Emissivity (ε)

Question 43

Stefan– Boltzmann constant (σ )

Answer 43

5.67 x 10^-8 W/m^2 K^4

Question 44

Stefan– Boltzmann constant (σ )

Answer 44

0.1714 x 10^-8 Btu/h . ft^2°R^4

Question 45

energy transfer between a solid surface

Answer 45

Convection

Question 46

adjacent gas or liquid at another temperature

Answer 46

Convection

Question 47

heat transfer coefficient

Answer 47

not a thermodynamic property

Question 48

Similarities of Heat and Work

Answer 48

- both transient phenomena - Systems never possess heat or work, but either or both cross - boundary phenomena - Both are observed only at the boundary of the system, and both represent energy crossing the boundary - Both heat and work are path functions and inexact differentials.

Question 49

What is Transient

Answer 49

the evaluation of how a system responds to fixed and varying boundary conditions over time

Question 50

APPLICATION of the conservation of energy principle to heat and thermodynamic

Answer 50

First law of themodynamics

Question 51

The change in internal energy of a system is equal to the heat added to the system minus the work done by the system

Answer 51

Energy Balance for Closed Systems

Question 52

Energy balance in differential form

Answer 52

dE = δQ (.) - W (.)

Question 53

The instantaneous time rate form of the energy balance is

Answer 53

dE/dt = Q (.) - W (.)

Question 54

Rate form of the energy balance

Answer 54

Time rate of change of the energy contained within the system at time t = Net rate at which energy is being transferred in by heat transfer at time t - Net rate at which energy is being transferred out by work at time t