thermal physics Flashcards
In the kelvin scale the temperture of a particle is proportional to
It’s energy.
What do all of the gas laws apply to?
A fixed mass of gas.
What is boyle’s law?
At a constant temperature, the pressure and volume of a gas are inversely proportional.
pv=constant
If you had a graph showing the inverse property of boyle’s law, and you increased the temperture, what would that change do?
It would move further away from the origin, to the north east.
What is Charles law?
At a constant pressure, the volume of a gas is directly proportional to its absolute temperature.
What is the pressure law?
At a constant volume, the pressure of a gas is directly proportional to its temperature.
At what point does a temp/pressure or volume graph hit the x axis?
At absolute zero.
what do all the constants in the ideal gas equation mean?
p=pressure T=temp V=volume n=no. of moles. R=molar gas constant.
in what conditions does the ideal gas equation work well?
Low pressure and high temperature.
what does Nₐ mean?
the no. of particles in one mole of something.
what does N mean?
the total no. of molecules.
what is the boltzmann constant equal to?
R/Nₐ
what is the equation of state?
pV=NkT
what is the root mean square speed?
Square all the speeds, find the mean and find the square root. It is the most probable speed of the particles.
What do you have to assume for the derivation of the pressure of an ideal gas equation?
Particles has a negligible volume compared with the volume of the container.
Any forces that act during a collision are instantaneous.
There are no attractive forces between the particles
All collisions are elastic
They follow netwtons’s laws.
They move rapidly and randomly
It contains a large no. of particles.
What happens to the boltzmann distribution when temperature increases?
The average particle speed increases.
The maximum particle speed increases.
The distribution curve becomes more spread out.
Peak gets lower.
what is on the axis of the boltzmann distribution?
y= proportion of particles with a given speed
x=particle speed
what is m in the gas equations?
The mass of one particle of gas.
what is specific heat capacity?
The amount of energy needed to raise the temperature of 1 kg of a substance by 1K
What is specific latent heat?
the specific latent heat of fusion or vaporisation is the quantity of thermal energy needed to change the the state of 1 kg of substance without a change in Temperature.
What is the symbol and unit of specific latent heat?
I and J kg^-1
What is random motion?
Particles have a range of speeds, no preferred direction of movment.
What is absolute zero?
The point with minimum internal energy
What is the triple point?
Temperature and pressure at which a substance can exist in all 3 phases
What is internal energy?
Energy associated with the random disordered motion of molecules.
Sum of the random distribution of the kinetic and potential energies of the object’s molecules.
What is the specific heat capacity ?
The energy required to raise the temp of 1 kg of a material by 1 k without a change in state.
If you are conducting an experiment to find the specific heat capacity of a material by heating with a heater and measuring temperature, what precautions do you make?
Let heater reach operating temperature.
Insulate heat lose to surroundings.
Ensure good thermal contact.
Why is the specific heat of vaporisation greater than that of fusion?
More energy is needed to separate out molecules than break solid bonds.
More work done against atmospheric pressure.
Greater change in potential energy.
What is an ideal gas?
Can’t be liquified
Obey’s Boyle’s law at all temperatures.
Molecules have negligible volume.
Why do smoke particles move?
They are bombarded by air molecules.
Graph of pressure against volume. What is the effect of temperature?
Inversely proportional curve.
Increasing temp moves the curve North East, further away from the origin
What are n and N in thermal equations?
n= number of moles N= number of molecules
What is specific heat capacity?
The energy needed to raise the temperature of 1kg of material by 1 kelvin with no change in state.
