Gases

Question 1

What are the properties of gases?

Answer 1

• Does not have high density (unlike solids and liquids)
• Expands its shape and volume to fill the container (solids have a fixed shape and volume, liquids have a fixed volume)
• A type of fluid
• Moves faster

Question 2

What is pressure?

Answer 2

The force exerted on the walls of a container; the force per area of the number of collisions. More collisions = more pressure.

Question 3

What happens to pressure as temperature increases?

Answer 3

Pressure will also increase. Temperature and pressure are directly proportional.

Question 4

What happens to pressure as moles increases?

Answer 4

Pressure will also increase. Moles and pressure are directly proportional.

Question 5

What happens to pressure as volume increases?

Answer 5

Pressure will decrease. Volume and pressure are inversely proportional.

Question 6

What is partial pressure?

Answer 6

The pressure exerted by each individual gas in a mixture

Question 7

What is total pressure?

Answer 7

The sum of all partial pressures

Question 8

What is ideal and real gas behaviour?

Answer 8

• Move in a straight line
• Move at different speeds
• Have random motion (not all moving in the same direction)

Question 9

What are the postulates of kinetic molecular theory of gases?

Answer 9

• Particles are in continuous random motion, and travel in straight lines until they hit other particles or the walls to change direction
• Volume of particles is negligibly small compared to the distances between them in the container
• Repulsive and attractive forces are negligible
• No energy lost in collisions (with other particles and the wall), making collisions elastic. This is due to the negligible repulsive and attractive forces
• Average kinetic energy depends on temperature

Question 10

When can we not assume gases behave ideally?

Answer 10

At high pressures or very low temperatures