20 Ideal Gases

Which one of the graphs below shows the relationship between the internal energy of an ideal gas (y-axis) and the absolute temperature of the gas (x-axis)?

• A

• B

• C

• D

The temperature of a room increases from 283K to 293K. The r.m.s. speed of the air molecules in the room increases by a factor of

• 1.02

• 1.04

• 1.41

• 2.00

A fixed mass of an ideal gas initially has a volume V and an absolute temperature T. Its initial pressure could be doubled by changing its volume and temperature to

• V/2 and 4T

• V/4 and T/2

• 2V and T/4

• 4V and 2T

What is the total internal energy of 2.4 mol of an ideal gas which has a temperature of 15 °C?

• 6.0 × 10^–21 J

• 1.4 × 10^–20 J

• 4.5 × 10² J

• 8.6 × 10³ J

The diagram shows a p-V graph for a fixed mass of gas. The volume increases from V₁ to V₂ while the pressure falls from p₁ to p₂.

Which one of the paths A, B, C or D will result in the greatest amount of work being done by the gas?

• A

• B

• C

• D

Pressure is caused by:

• Gas molecules colliding with surfaces

• Gas molecules reacting with each other

• Gas molecules colliding with each other

• Gravity

A hypothetical gas that perfectly fits all the assumptions of the kinetic molecular theory is known as

• real gas

• ideal gas

• imaginary gas

• perfect gas

Under what conditions do real gases behave most like an ideal gas?

• Low temperature and low pressure

• Low temperature and high pressure

• High temperature and low pressure

• High temperature and high pressure

For an ideal gas at constant temperature and pressure p at volume V, what affect would halving the pressure have on the volume?

• volume would double

• volume would halve

• volume would triple

• none

For an ideal gas several assumptions are made about the particles including

• they collide elastically with each other and the container wall

• they experience significant intermolecular forces

• the volume they occupy as individual particles is insignificant compared to the volume of the container

• there are a very large number of particles inside the container