Gases and the Kinetic Theory

Question 1

What is pressure?

Answer 1

The force exerted per unit area

Question 2

How can you measure pressure?

Answer 2

Pressure gauge

Question 3

What is the cause of pressure of a gas?

Answer 3

The force the gas particles exert on the walls of its container (or on objects inside the gas)

Question 4

What 3 things can affect the motion of particles?

Answer 4

• Pressure
• Volume (of container)
• Temperature

Question 5

What happens to volume as pressure increases?

Answer 5

Volume decreases

Question 6

What happens to pressure as temperature increases?

Answer 6

Pressure increases

Question 7

What happens to volume as temperature increases?

Answer 7

Volume increases

Question 8

What is Boyle’s Law?

Temperature is constant

Answer 8

As volume increases, pressure decreases
Pressure x Volume = constant
P1 x V1 = P2 x V2

Question 9

What is the Pressure Law?

Answer 9

Given mass and constant volume of an ideal gas, pressure exerted on sides of container is directly proportional to its absolute temperature
P divide by T = constant

Question 10

What is Charles’ Law?

Answer 10

Given mass of an ideal gas at constant pressure, volume is directly proportional to its absolute temperature assuming a closed system
V divide by T = constant

Question 11

If gas laws are combined (Ideal Gas Equation)

Answer 11

P1 x V1 divide by T1 = P2 x V2 divide by T2

Question 12

Which is the least energetic and which is the most?

Solid, liquid, gas

Answer 12

• Solid is the least energetic

- Gas is the most energetic

Question 13

Description of Solid

Answer 13

• Holds shape

- Fixed volume

Question 14

Description of Liquid

Answer 14

• Shape of container
• Fixed volume
• Free surface

Question 15

Description of Gas

Answer 15

• Shape of container

- Volume of container

Question 16

Kinetic Theory

Answer 16

Idea that a gas is made from tiny particles that are constantly, randomly moving. All collisions are elastic (no KE lost)

Question 17

How is pressure created in gases?

Answer 17

Gas particles colliding with inside surface of container

Question 18

As volume decreases, pressure increases. This means that…

Answer 18

Pressure is inversely proportional to volume

Question 19

When temperature (Kelvin) is doubled, pressure doubles. This means that…

Answer 19

Pressure is directly proportional to temperature

Question 20

When temperature (Kelvin) is doubled, volume doubles. This means that…

Answer 20

Volume is directly proportional to temperature

Question 21

Explain how volume of gas decreases as pressure increases using kinetic theory (QWC)

Answer 21

As volume decreases, the same number of gas particles are moving around in smaller space and so are closer together. Average speed of particles remains the same at constant temperature. But, there are more particles hitting inside of container each second. When particles strike wall of container there’s a change in momentum of particles (Newton’s 2nd law) which results in a force on particles creating an equal but opposite force on walls (Newton’s 3rd law). More force acting on inside surface. Since P = F/A , pressure increases

Question 22

Why is conduction slow in gases?

Answer 22

Atoms are further apart so collide less often

Question 23

What happens during convection?

Answer 23

Liquids/gases heated up which leads to their atoms/molecules colliding at higher speeds more often