2.3 Thermodynamics Flashcards
What is 0°C in Kelvin?
°C + 273.15
What is the equation to work out °C from °F?
(5/9°F)-32
What is the equation to work out degrees F from C?
(9/5°C)+32
At what temperature does mercury freeze?
-34°C
What is the purpose of a Wheatstone Bridge circuit?
It is a circuit that changes resistance in response to a change in temperature.
What are the common metals used in a Thermocouple?
Copper and Constantan
What is 1 Calorie in Joules?
(Calorie - Amount of heat needed to raise temperature of 1kg of water by 1 degree C)
4186J
What is 1 BTU in Joules?
(BTU - Amount of heat needed to raise temperature of 1lb of water by 1 degree F)
1055J (0.252 Calorie)
What is the formula to calculate the heat capacity?
Q = mC Δ T
Q = Heat gained or lost
m = Mass
C = Specific heat of substance
T = Temperature
What is the formula for latent heat?
Q = mL
M = Mass
L = Specific latency
What are the three types of heat transfer?
Conduction
Convection
Radiation
What is the temperature at which Water has the greatest density?
4°C
What is Entropy?
A quantitative measure of the amount of thermal energy not available to do work for a closed system. It is the unavailable energy.
How many laws are there in thermodynamics?
Four
What is the First law?
The total increase in the energy of a system is equal to the increase in thermal energy plus the work done on the system.
What is the Second law?
Heat energy cannot be transferred from an object at a lower temperature to an object at a higher temperature without the addition of energy.
What is an Adiabatic process?
One with no heat transfer into or out of a system.
What is an Isochoric process?
It is a constant volume process.
What is an Isobaric process?
It is a constant pressure process.
What is an Isothermal process?
It is a constant temperature process.
What is Enthalpy?
It is the amount of energy in a gas capable of doing work.
It is a combination of internal energy, pressure and volume due to whenever a gas is heated.
What is an Isentropic process?
It is a constant entropy process. It is a reversible process due to no energy dissipating as heat.
What is Boyle’s law?
The Volume of a given mass of gas at a constant temperature is inversely proportional to pressure.
PV = Constant
P1V1 = P2V2
What is Avogadro’s law?
It states that equal volumes of all gases, at the same temperature and pressure, have the same number of molecules.
What is Charles’ law?
A volume of given mass of gas at constant pressure increases 1/273 of it’s volume at 0°C for every 1°C rise in temperature.
What is Gay-Lussac’s law?
The pressure of a given mass of gas at constant volume is proportional to it’s temperature.
P/T = Constant
P1 P2
=
T1 T2
What is the Brayton cycle?
Continuous combustion cycle for modern gas turbine engines.
What is the SI unit for Heat?
Joule
What is the relative density of copper (CU)?
8.9
What is the unit of density?
KG per cubic metre
If a fluid flows easily under it’s own weight, what is it said to have?
Low viscosity
1° increment on the °C scale is equal to what °F increment?
1.8°F
What is the triple point?
The temperature which water will exist as a solid, liquid and gas all at the same time
What is the Dew point?
The temperature at which condensation actually occurs.
