Thermodynamics & Heat Transfer

Question 1

Thermo: Properties of Substances - Phases of a Pure Substance

Ideal gas law (formula)

Answer 1

pV = nRT

Question 2

Thermo: Properties of Substances - Phases of a Pure Substance

What is a p-v-T diagram?

Answer 2

3D surface that predicts a substance’s phase based on the properties of presure, specific volume, and temp.

Question 3

Thermo: Properties of Substances - Phases of a Pure Substance

What is the vapor dome?

Answer 3

The bell-shaped diving line at the liquid-vapor region.

Question 3

Thermo: Properties of Substances - Phases of a Pure Substance

What other diagrams can be derived from a p-v-T diagram?

Answer 3

Pressur-Volume Phase Diagram (2D projection of the 3D p-v-T diagram, where one property is held constant. In this case, that is temperature.)

Vapor Dome Diagram

These are phase diagrams or equiplibrium diagrams.

Question 4

Thermo: Properties of Substances - Phases of a Pure Substance

Define the saturated liquid line?

Answer 4

Left-hand part of the vapor dome curve that separates the liquid phase from the liquid-vapor phase.

Question 5

Thermo: Properties of Substances - Phases of a Pure Substance

Define saturated vapor line?

Answer 5

Right-hand part of the vapor dome curve that separates the liquid-vapor phase from the vapor phase.

Question 6

Thermo: Properties of Substances - Phases of a Pure Substance

Define isobars?

Answer 6

Lines of constant pressure.

Question 7

Thermo: Properties of Substances - Phases of a Pure Substance

Above the vapor dome, the phase is what?

Answer 7

Gas

Question 8

Thermo: Properties of Substances - Phases of a Pure Substance

What is the critical isobar?

Answer 8

The dividing line between liquid and gas that intersects the topmost part of the vapor dome**.

Question 9

Thermo: Properties of Substances - Phases of a Pure Substance

What is the critical point?

Answer 9

The highest point of the vapor dome.

Question 10

Thermo: Properties of Substances - Phases of a Pure Substance

What is the triple point?

Answer 10

A unique state at which solid, liquid, and gaseous phases can coexist.

Question 11

Thermo: Properties of Substances - Phases of a Pure Substance

Define isotherms?

Answer 11

The lines of constant temperature.

Question 12

Thermo: Properties of Substances - Phases of a Pure Substance

‘1. A substance is a subcooled liquid if:

Answer 12

its temperature is less than the saturation temperature corresponding to its pressure.

Question 13

Thermo: Properties of Substances - Phases of a Pure Substance

‘2. A substance is in the liquid-vapor region if:

Answer 13

its temperature is equal to the saturation temperature corresponding to its pressure.

Question 14

Thermo: Properties of Substances - Phases of a Pure Substance

‘3. A substance is a superheated vapor if:

Answer 14

its temperature is greater than the saturation temperature corresponding to its pressure.

Question 15

Thermo: Properties of Substances - Phases of a Pure Substance

‘4. A substance is a subcooled liquid if:

Answer 15

its pressure is greater than the saturation pressure corresoponding to its temperature.

Question 16

Thermo: Properties of Substances - Phases of a Pure Substance

‘5. A substance is in the liquid-vapor region if:

Answer 16

its pressure is equal to the saturation pressure corresponding to its temperature.

Question 17

Thermo: Properties of Substances - Phases of a Pure Substance

‘6. A substance is a superheated vapor if:

Answer 17

its pressure is less than the saturation pressure corresponding to its temperature.

Question 18

Thermo: Properties of Substances - State Functions (Properties)

Define intensive properties?

Answer 18

Properties that are independent of the amount of a substance present.

Question 19

Thermo: Properties of Substances - State Functions (Properties)

Define extensive properties?

Answer 19

Properties that are dependent of the amount of a substance present.

Question 20

Thermo: Properties of Substances - State Functions (Properties)

Examples of intensive properties:

Answer 20

temperature, pressure, stress

Question 21

Thermo: Properties of Substances - State Functions (Properties)

Examples of extensive properties:

Answer 21

volume, strain, charge, mass

Question 22

Thermo: Properties of Substances - State Functions (Properties)

Rankine scale (formula)

Answer 22

Tf + 459.67 degrees

Question 23

Thermo: Properties of Substances - State Functions (Properties)

Kelvin scale (formula)

Answer 23

Tc + 273.15 degrees

Question 24

Thermo: Properties of Substances - State Functions (Properties)

Define enthalpy?

Answer 24

Represents the total useful energy of a substance.

Question 25

Thermo: Properties of Substances - State Functions (Properties)

Define entropy?

Answer 25

A measure of the energy that is no longer available to perform useful work within the current environment.

Question 26

Thermo: Properties of Substances - State Functions (Properties)

Formula for heat energy (Q)?

Answer 26

Q = mcΔT

Question 27

Thermo: Properties of Substances - State Functions (Properties)

Formula for quality (x)?

Answer 27

x = Mvapor / Mvapor + Mliquid

Question 28

Thermo: Properties of Substances - Ideal Gases

Another ideal gas relationship for pressure, volume, and temperature? (formula)

Answer 28

p1V1 / T1 = p2V2 / T2

Question 29

Thermo: Properties of Substances - Ideal Gases

How can you calculate the number of moles (n) of a substance?

(explanation and formula)

Answer 29

Using the mass (m) and molecular weight (MW).

n = m / MW

Question 30

Thermo: Properties of Substances - Ideal Gases

Define isentropic processes.

Answer 30

entropy is constant

Question 31

Thermo: Properties of Substances - Speed of Sound & Mach

What is a Mach number? (definition)

Answer 31

The ratio of an object’s speed to the speed of sound in the medium through which the object is traveling.