Thermal Flashcards
Ideal gas equation
pV = nRT
(All KE energy, no PE energy as no interaction between particles and follows RAVED)
First law of thermodynamics
∆U = Q - W
Q = heat added to the system
W = work done by the system
Work is done on water and therefore due to 1st law of thermodynamics is converted to thermal energy
RAVED
Random motion
Attraction between particles is negligible
Volume is negligible
Elastic collisions
Duration of collisions is negligible
Rms
Square the value
Find the mean of those value
Square root the mean
Brownian motion
Random motion of particles due to collision with other fast moving particles
Absolute zero
1) gas laws
2) kinetic theory
1) when pressure/volume extrapolates to zero
2) when random motion of particles stop / kinetic energy is zero
Specific latent heat of fusion Vs vaporisation
Fusion = between solid and liquid
Vaporisation = liquid and gas
Pressure law
P/T = constant
As P increases so does T
Ideal gas law
pV/T = constant
Dependant on number of moles
Moles equation
Moles = grams/rams
What does 3RT/2Na find the KE of?
A molecule and therefore multiply by Na for the KE of a mole
Formula for if 2 substances touch and reach common temperature
m1c1(T - T1) = m2c2(T2 - T)
What happens when a substance is changing state
It breaks ‘some’ of the atomic bonds.
What is the area of pressure against volume graph
P∆V = workdone
What is emitted when a nucleus is excited and when an electron is excited?
1) Gamma primarily / EM waves
2) Photons (packets of EM waves)
Explain why the molecules of gas exert a force on the walls of a container? Refer to Newton’s laws
Change in momentum= 2x mu
Therefore change in momentum requires force (N2)
Wall must exert force on molecule
Therefore vice versa (N3)
Explain in terms of KE theory why a pressure is exerted by the gas on the piston?
Atoms collide with piston, they change direction and therefore momentum. As f = ∆(mv)/t they exert force on the piston.
Impulse Vs force when comparing to momentum
Impulse is the change in momentum of an object, and force is the rate of change of momentum. Mathematically, impulse is equal to the force applied to an object multiplied by the time during which the force is applied. So, force can be expressed as the derivative of momentum with respect to time.
When a pump is working at higher speeds why is the rise in temperature in the water it’s circulating greater?
Pump does work and due to 1st law of thermodynamics temperature increases
What is an isothermal change?
A process that occurs at a constant temperature
