Ideal And Real Gases

Question 1

What is pressure

Answer 1

Force per unit area

Question 2

What determines pressure

Answer 2

The number of collisions per unit area of the gas molecules against the wall of the container

Question 3

What two factors affect pressure

Answer 3

Velocity and the mass of the gas molecules

Question 4

What is an ideal gas

Answer 4

A theoretical gas that obeys all ideal gas laws under all circumstances of temperature and pressure

Question 5

What are the seven properties of an ideal gas

Answer 5

1. all molecules are the same
2. gas molecules do not occupy volume and thus the volume of the gas is determined by the container it is in
3. no forces of attraction or repulsion between the gas molecules and amount the molecules and the walls of the container, except when the molecules collide with one another against the wall of the container
4. All collisions are elastic
5. The temperature of a gas is a measure of its average kinetic energy
6. The pressure exerted by a gas is due to the collision of gas molecules on a unit area in a unit time
7. There is no movement of gas molecules at 0K this is called the absolute zero

Question 6

When will real gasses show ideal gas behaviour

Answer 6

At a high temperature and low pressure

Question 7

What are the real gasses that are nearest to an ideal gas and why

Answer 7

Hydrogen and helium because:
1. They are very small and non-polar with weak London forces
2. They are so small the volume of the particles will only contribute to the total gas volume at an extremely high temperature

Question 8

What are the three ideal gas laws

Answer 8

Boyles law: volume is inversely proportional to pressure

Charles law: volume is directly proportional to volume

Gay-Lussacs law: pressure is directly proportional to temperature

Question 9

What does boyles law demonstrate

Answer 9

The volume of an enclosed mass of gas is inversely proportional to the pressure, provided that the temperature remains constant

Question 10

What for Charles law demonstrate

Answer 10

The volume of a fixed quantity of gas is directly proportional to the absolute temperature, if the pressure is kept constant

Question 11

What does gay-lussacs law demonstrate

Answer 11

The pressure of a fixed quantity is directly proportional to the absolute temperature, if the volume is kept constant