IDEAL GASES

Question 1

Reiterate the SI base units

Answer 1

Kg, m, s, A, mol, K, cd

Question 2

one mole is defined as

Answer 2

the amount of substance that contains as many elementary entities as there are atoms in 12g of carbon-12.

Question 3

What is the Avogadro constant ?

Answer 3

6.02 x 10^23, the number of atoms in 12g of carbon-12.

Question 4

the total no of atoms or molecules in a substance, N, is

Answer 4

N = n x Nₐ, where Nₐ is the Avogadro constant and n is the number of moles in a substance

Question 5

How to calculate the molar mass ?

Answer 5

M = m / n, where m is the total mass of the substance and M is the molar mass aka the mass of one mole

Question 6

What is the kinetic theory of matter?

Answer 6

is a model used to describe the behavior of the atoms or molecules in an ideal gas, as real gases have complex behaviors, hence a number of assumptions are made.

Question 7

what are the assumptions that the the kinetic theory of matter uses?

Answer 7

• the gas contains a very large no of atoms or molecules moving in random directions with random speeds
• the atoms or molecules of the gas occupy a negligible volume compared to the volume of the container
• the collisions of atoms or molecules with each other and the container are completely elastic
• the time of collisions between the particles is negligible compared to the time between collisions
• electrostatic forces between atoms or molecules are negligible except during collisions

Question 8

Using the newton’s law’s assumptions and the assumptions from the kinetic theory of matter

Answer 8

we can describe how molecules or atoms cause pressure in an ideal gas

Question 9

the total change in momentum for a colliding particle against the walls of the container is…

Answer 9

-2mu

Question 10

pV=

Answer 10

nRt

Question 11

pV=

Answer 11

pV=1/3 x N x ¬(c^2)¬

Question 12

pV=

Answer 12

pV=nkNat

Question 13

derive

Question 14

Whats the name of the distribution that shows different particles speed at different temperatures

Answer 14

Maxwell Boltzmann Distribution

Question 15

What’s the name of the distribution that shows different particles speed at different temperatures

Answer 15

Maxwell Boltzmann Distribution

Question 16

What effect does increasing the temperature of the gas has on the Maxwell Boltzmann distribution?

Answer 16

The hotter the temperature, the greater the range of speeds. The most modal speed and r.m.s. increases and the distribution becomes more spread out

Question 17

The Boltzmann constant

Answer 17

k=R/Na=1.38 x 10^-23

Question 18

pV=

Answer 18

pV=Nkt

Question 19

What those Boyle’s Law states?

Answer 19

Boyle’s Law states that for a fixed mass of an ideal gas at a constant temperature, its pressure is inversely proportional to its volume

Question 20

Why do we have to increase the pressure of the gas slowly when conducting an experiment to explore the validation of Boyle’s Law?

Answer 20

Because increasing the pressure too quickly will lead to a change in temperature, meaning that Boyle’s Law cannot be verified using these affected values

Question 21

what does the left hand side of this equation represents?

1/2(m(¬c¬)^2)=3/2(kT)

Answer 21

The average kinetic energy of each particle in the gas

Question 22

Brownian motion is caused by.

Answer 22

collisions between air particles and smoke particles

Question 23

A mixture of argon atoms and helium atoms in a cylinder enclosed with a piston. The mixture is at a temperature of 310K. Compare the kinetic energy of the argon atoms and helium atoms in the mixture.

Answer 23

Both gases have the same mean or average kinetic energy

Question 24

Explain, in terms of the kinetic theory model, why a pressure is exerted by the gas on the piston.

Answer 24

The particles constantly collide with the walls of the piston and change momentum upon collision, exerting a force or impulse that it is equal to the rate of change in momentum.

Question 25

Use the ideas from kinetic theory to explain why gas molecules have a range of speeds but are unlikely to have speeds much greater than the most common speed.

Answer 25

Particles collide with each other, exchanging energies. For a particle to have a much greater speed than the common speed, they will have to gain a lot of energy by colliding successively and frequently, which is unlikely.

Question 26

Explain what is meant by an ideal gas

Answer 26

In an ideal gas particles have negligible volume compared to that of the container. Also, all collisions with the container other particles are perfectly elastic and there are no interactions between particles except during collisions.