Thermal physics Flashcards
what is internal energy
sum of kinetic energy and potential energy of all particles in a substance (only one can change at a time)
what happens as particles melt or evaporate (energy transfer)
particles gain potential energy. E is being used to overcome electrostatic forces of attraction between particles.
Describe specific heat capacity
amount of e required to raise the temp of 1kg of a substance by 1k.
describe specific latent heat
the e required to change the state of 1kg of a substance.
describe latent heat
& the difference beetween slh & lh.
the total e required to change the state of a substance.
slh - per kg
lh- total e
what is absolute 0?
where all partciles have 0 ke. ( 0 pressure & 0 volume). 0k=-273C
how is absolute 0 found?
plot a graph of Pressure or volume against T. extrapolate to find where it crosses the X axis. That point is absolute O in degrees C
what is boyles law?
pressure is inversely proportional to volume at constant T.
p squiggle 1/v
what does isothermal mean?
at constant temp
what is charles’s law?
volume is proportional to temp at constant p
v squiggle t
Gas Law PV = NkT what does N stand for
number of molecules (big number = big N)
Gas Law PV = nRT what does n R stand for
n number of moles ( little number little n )
R gas constant 8.31
when to use (P1V1)/T1= (P2V2)/T2
if all three are changing but number of molecules are constant
when to use P1V1 = P2V2
if temperature is constant
Name the conditions for an ideal gass to work (RAVED)
R. motion must be Random ( brownian motion)
A. NO electrostatic attraction between molecules
V. Volume of gas must be negligible to volume of container
E. all collisions are Elastic
D. Duration of collisions are negligible compared to time between them)
Kinetic theory equation. Derive force of a particle.
force = rate of change of momentum.
momentum = 2mu (momentum there + momentum back)
time taken = 2L/u ( distance 2L over velocity in that direction u)
kinetic theory equations. Derive pressure from a particle.
1.) Pressure = force / area
2.) force = (mu^2) / L
3.) Area = L^2 as we are only looking for one side
What is C rms and how to derive it.
combination of speeds in all 3 directions.
How to find work done on a P-V graph.
W= Area under the graph
If a gas is compressed, work is done on it.
If it expands, it is doing work
Arrow will change in volume.
Prove that all molecules in a gas have the same kinetic energy if at the same temperature.
ke= 3/2 kT
