Module 5.1 - Thermal Physics

What is an absolute temperature?

A temperature value that is relative to absolute zero

Define absolute zero

The lowest possible temperature in a system where all the particles have no kinetic energy

What is Brownian motion?

The random movement of visible particles in a fluid as a result of collisions of randomly moving atoms or molecules

What is Boyle’s Law?

pV=constant

What energy changes happen during phase changes?

Potential energy of the particles changes but kinetic energy stays the same

What energy changes happen when a substance is being heated but no phase change happens?

Kinetic energy of the particles changes but potential energy stays the same

What does it mean for objects to be in thermal equilibrium?

All objects in the system have the same temperature and there is no net energy transfer between them

What is the equation for the number of particles in a substance?

number of particles=number of moles x Avogadro’s constant

What are the four assumptions you need to make for the Kinetic Theory of Gases?

There are a large number of particles moving randomly; individual particles occupy negligible volume compared to the volume of the gas; all collisions are perfectly elastic and the time spent in collision is negligible compared to the time between collisions; there are negligible forces between particles except during collisions

What is the ideal gas law equation for number of moles?

pV=nRT; p is pressure; V is volume; n is number of moles; R is the molar gas constant; T is temperature

What is the value of the molar gas constant?

8.31 JK^-1mol^-1

What is the ideal gas law equation for number of particles?

pV=NkT; p is pressure; V is volume; N is number of particles; k is Boltzmann’s constant; T is temperature

What is Boyle’s Law in equation form?

p1V1=p2V2

What is the condition required for Boyle’s Law?

Constant temperature

What is Gay-Lussac’s Law in equation form?

P1/T1=P2/T2

What order do the average velocities appear in the Maxwell-Boltzmann distribution?

Most probable speed, mean speed, root mean squared speed

What is the ideal gas law equation that includes the rms speed of the particles (c² has a line on it)?

pV=1/3Nmc²; p is pressure; V is volume; N is number of particles; m is mass of a single molecule; c² is the rms speed of the particles

What is the ideal gas law equation that includes the Boltzmann’s constant?

1/2mc²=3/2kT; m is mass of a single molecule; c² is the rms speed of the particles; k is Boltzmann’s constant; T is temperature, K

What is the internal energy of a system?

The sum of the kinetic and potential energies of every particle

How does the specific heat capacity of a liquid compare to that of its solid form?

The specific heat capacity of a liquid is less than its solid form

Define specific heat capacity

The amount of energy required to heat 1kg of a substance by 1K

Define specific latent heat

The amount of energy to change the phase of a substance but not its temperature

How do you calculate the root mean squared speed?

Sum the squares of the speeds, find the mean, square root

What is the relationship between the Boltzmann constant and Avogadro’s number?

Boltzmann constant=molar gas constant/Avogadro’s number