Gas Works

Question 1

Relationship between pressure and temperature.

Answer 1

For HVACR purposes, the crucial point at which pressure and temperature com together is point at which evaporation or condensation occurs, depending upon whether heat is being added or removed. The Heat/temperature char of water points out some important things about pressure and temperature.

Question 2

Sub cooling

Answer 2

Liquid at the temperature blow its boiling point.

Question 3

Super heat zone

Answer 3

Heat added to vapor above its saturated condition.

Question 4

Latent heat

Answer 4

Heat added or taken away for 1 pound of a substance that causes a change in state, but not a change in temperature.

Question 5

Heat of evaporation and condensation are _________ heat

Answer 5

Latent

Question 6

Sub Cooling zone

Answer 6

Liquid at a temperature below its boiling point (sensible heat)

Question 7

Super heat zone

Answer 7

Heat added to Vapor above its saturated condition.

Question 8

Heat of freezing

Answer 8

Taking heat from water to get ice. (Latent heat)

Question 9

Heat of melting

Answer 9

Adding heat to ice to get water. (Latent heat) 144 btu

Question 10

Sensible heat

Answer 10

Heat added for removed from a substance that causes a change in temperature.

Question 11

What happens to the boiling point of temperature if the pressure is increased?

Answer 11

Boiling point temperature go up.

Water is radiation in car boils a 250 degrees. Because it is held at 15 pounds of pressure.

Question 12

Saturated Condition

Answer 12

Liquid and vapor in the same container under the same conditions

Question 13

Inch Hq = micron= cm=mm

Answer 13

1.00 inch Hg = 25.400 microns=2.54cm=25.4mm
.100 inch Hg = 2,540 microns=.254cm=2.54mm
.039 inch hg = 1000 microns = .100cm=1.00mm

Question 14

Micron

Answer 14

1 micron = 1 millionth of a meter.

Question 15

Work

Answer 15

Force x distance

Question 16

Power

Answer 16

Work x time

Question 17

Boyle’s Law

Answer 17

P up V down T =
P down V goes up T=
With a constant temperature
P = pressure
V = volume
T = temperature

Question 18

Charles law

Answer 18

V up T up P =
V down T down P =
P up T up V=
P up T up V=

Question 19

Pascal law

Answer 19

Pressure on a fluid is transmitted equally in all directions.

Example: Brakes in your car

Question 20

Fluid

Answer 20

Is something the will flow. Liquid or a vapor or both.

Question 21

Critical pressure

Answer 21

Is a condition of fluids, including refrigerants at which liquid and gas have the same properties. This pressure is so high that the physical state of liquid and vapor merged

Question 22

Critical temperature

Answer 22

Is the highest temperature at which a gas can still be liquefied by the application of pressure. If vapor temperature is above the critical temperature, increasing pressure upon the vapor will not cause it to condense into liquid.

Question 23

Specific Gravity

Answer 23

Is the ratio of weight or mass of a given volume of a substance that of the same volume of a standard

With refrigerants the standard is air

Propane will sink. (It is heavier the air) Natural gas goes up (it is lighter than air)

Question 24

Saturated

Answer 24

A solution is said to be saturated when it can dissolve or contain no more of a substance and additional amounts will appear as precipitate. The point at which a change of state will occur

Question 25

Saturated condition

Answer 25

Term used to indicate the boiling or condensing point of a substance, which is dictated by a specific combination of temperature and pressure.

Question 26

Saturated liquid

Answer 26

A saturated liquid contains as much heat (thermal energy) as it can without boiling (changing state)

Question 27

Saturated vapor

Answer 27

Vapor at the same pressure and temperature as the liquid it contacts

Question 28

Vaoporization

Answer 28

The change of a liquid into a gaseous state

Question 29

Condensation

Answer 29

Liquid or droplets which form when a gas or vapor is cooled below its dew point

Question 30

Boiling point

Answer 30

The temperature at which a vapor pressure of liquid is equal to the surrounding atmospheric pressure so that liquid becomes a vapor, ie the temperature at which upward pressure of the molecules escaping from the surface equals the downward presume of the atmosphere.

Question 31

Change of state

Answer 31

The process that a substance (either a compound or element) goes through when changing from one physical state to another. Water to steam

Question 32

Vapor pressure

Answer 32

The pressure exerted by a saturated vapor above its own liquid in a closed container.

Question 33

Equilibrium

Answer 33

Conditions that exist a saturation or balance.

Question 34

Refrigerant

Answer 34

A substance used is a refrigeration system to absorb heat in the evaporator by changing liquid to gas and releasing this heat form the condenser when the substance returns to a liquid state.

Question 35

Saturated presure

Answer 35

The force in a pressure vessel that matches the temperature of certain contained gas at a condition where any removed heat would cause condensation, and added heat would cause evaporation

Question 36

Three names of the men for the gas laws

Answer 36

Robert Boyle Jacques Charles John Dalton

Question 37

Temperature

Answer 37

As a measurement of the intensity of heat present in a substance

Question 38

Absolute zero

Answer 38

Represents the complete absence of heat in a substance - 460 degrees below zero. - 273 Celsius

Question 39

Change Fahrenheit to Rankine

Answer 39

Add 460 is above zero | Subtract 460 if below zero

Question 40

Presure

Answer 40

As force per until area | Sea level 14.696

Question 41

Volume

Answer 41

Is space that a substance occupies or can occupy

Question 42

Pressure conversion | Convert barometric pressure to psia

Answer 42

Divid barometric pressure by 2.036

Question 43

Convert PSIA to HG

Answer 43

Multiply the psia by 2.036

Question 44

Calculate pressure at Constant Volume Take a 1 ft cylinder of nitrogen at 70 degrees. A gauge on it he shows 700 psig. What will the gauge show if the cylinder temp is raise 90

Answer 44

70F +460=530 t1 90F + 460= 550 t2 700 psig + 14.7= 714.7 or p1 P2 is 550r by 714 psia then devid by 530 the answer is 741.7