Temperature and Ideal Gases

Question 1

Define temperature and heat.

Answer 1

Temperature is a measure of degree of hotness of an object by quantifying the average kinetic energy of the molecules that make up the object.
Heat is the thermal energy that flows from region of higher temperature to region of lower temperature due to a difference in temperature between the two regions.

Question 2

Define thermal equlibrium.

Answer 2

When two bodies are in thermal equilibrium, there is no net transfer of thermal energy between the bodies in thermal contact and the bodies that are at the same temperature. (There is still heat transfer, but both are at the same rate so no net transfer)

Question 3

Formula for number of moles

Answer 3

n = N/NA = m/Mr
Mr = Molar mass/Atomic mass
NA = 6.02e23

Question 4

What are Pressure Law, Charles’ Law and Boyle’s Law?

Answer 4

Pressure at constant volume is directly proportional to temperature.
Volume at constant pressure is directly proportional to temperature.
Pressure at constant temperature is inversely proportional to volume.

Question 5

What is an ideal gas?

Answer 5

An ideal gas is a theoretical gas that obeys the equation of state (pV=nRT) at all pressure, volume and temperature.
pV = nRT, R = 8.31
pV = NkT, k = 1.38e-23

Question 6

What is the kinetic theory equation?

Answer 6

pV = Nmc^2/3
m = mass of single particle

Question 7

What is root-mean-square speed?

Answer 7

Root-mean-square speed is the square root of the mean of the squared speed.
The particles in the gas are moving in random speed and direction. Most of the time, there is a range of speeds that these particles possess. The root-mean-square speed is an indicative speed which, when possessed by all the gas particles, will keep the total kinetic energy of the particles unchanged.

Question 8

What is the energy of one particle and for N particles?

Answer 8

E(1) = 3kT/2
E(N) = 3NkT/2 = 3nRT/2 = 3pV/2

Question 9

Assumption of kinetic theory of gases

Answer 9

Any gas made of large number of particles

Particles in constant and random motion

Particles make perfectly elastic collisions (no loss or gain in KE)

Volume of particles negligible

Forces between particles negligible except for collisions

Duration of collisions is negligible