REF UNITS 1 to 2 Flashcards
(1.1) What is the boiling point of water in Fahrenheit?
212F
(1.2) What is the difference between heat and temperature?
heat is the energy applied to the material to raise its temperature.
(1.2) What is atmospheric pressure at sea level in psi?
14.696 Psi(a)
(1.2) Define absolute zero
the temperature where no heat is present (-460 F or 0 R).
(1.2) How do you convert Celsius to Fahrenheit?
Fahrenheit = (Celsius X 1.8) + 32
(1.2) How do you convert Fahrenheit to Celsius?
Celsius = (Fahrenheit - 32) ÷ 1.8
(1.2) How do you convert Fahrenheit to Rankine?
Add 460
(1.2) How do you convert Celsius to Kelvin?
Add 273
(1.3) What does the first law of thermodynamics state?
matter can neither be created nor destroyed.
(1.3) What does 1 BTU represent?
The amount of heat energy required to raise the temperature of 1 pound of water by 1 degree Fahrenheit.
(1.3) How are heating and air conditioning systems rated?
In BTUs/hr
(1.4) Define heat transfer by conduction
heat energy traveling from molecule to molecule in the same substance (like heating a copper pipe).
(1.5) Define heat transfer by Convection
heat energy applied to a fluid (like air or water) which heats surrounding objects.
(1.5) Define natural convection
The natural rise ad movement of heated air.
(1.6) How much are you heated if you stand double the distance away from a heat source?
a 4th of the heat experienced at the square root distance of where you are now.
(1.6) What is the only transfer of heat that can occur through a vacuum?
Radiation.
(1.7) What is the specific heat for water
1BTU/lb/F
(1.7) What is the specific heat of ice?
0.5BTU/lb/F
(1.7) What is the specific heat of steam?
0.5BTU/lb/F
(1.7) What is the specific heat of air?
0.24BTU/lb/F
(1.8) Define latent heat
The heat added to a substance that changes it’s state, but not its temperature
(1.8) What is the latent heat of fusion? (for water)
144BTU/lb
(1.8) What is the latent heat of vaporization/condensation (for water)?
970BTU/lb
(1.9) Define specific heat
the heat energy required to raise the temperature of 1 pound of a substance by 1 degree Fahrenheit
(1.12) What is atmospheric pressure also known as?
standard condition
(1.12) What tool uses mercury to measure atmospheric pressure?
a barmometer
(1.12) How many inches of mercury is atmospheric pressure at 70F?
29.92 inches
(1.12) How many inches of mercury does one psi equal?
2.036 Hg
(1.13) What does gauge manifold use to measure pressure?
bourdon tube
(2.2) Define mass
the property of matter that responds to gravitational attraction
(2.2) Define Weight
the downward force that an object applies when at rest.
(2.3) How is density measured?
lb/ft³
(2.3) What is the density of water?
62.4lb/ft³
(2.4) Define specific gravity
the density of a substance as a ratio compared to the density of water (expressed as a unitless number).
(2.5) Define specific volume
The inverse of density. The space occupied per 1 pound of the substance.
(2.6) What does Boyle’s law state?
P1 X V1 = P2 X V2
(2.6) What does Charles’ law state?
P1 ÷ T1 = P2 ÷ T2
(2.6) What is the name of the gas law that combines Boyle’s law and Charles’ law?
General Law of Perfect Gases
(2.6) What does Dalton’s law state?
P1 + P2 = P3
(2.12) How is work calculated and expressed?
work (ft-lb) = force (lbs) X distance (ft)
(2.13) How is horsepower measured?
amount of work done/min. 1 HP = 33,000 ft-lb/min
(2.14) How many watts is equal to 1HP?
746
