Topic 2.3: Gas Laws Questions

Outline two assumptions of the kinetic model of an ideal gas.

A tyre at 7 °C has a pressure of 200 kPa. It warms to 35 °C with no change in volume.

What is the new pressure?

0.75 mol of an ideal gas at 2.5 × 10⁵ Pa occupies 1.0 × 10⁻² m³.

Calculate its temperature.

A gas pushes a piston outwards quickly and its temperature falls.

Which is the best explanation?

A student verifies Boyle's law and finds that the product PV stays constant for a fixed mass of gas at constant temperature.

State the value being kept constant in this experiment, and state an appropriate SI unit for the constant PV.

A bicycle pump is pushed in quickly and the air inside warms up.

Which explanation uses the kinetic model correctly?

State the SI unit of the product pV for a gas.

A gas at 0 °C is heated at constant pressure until its volume doubles.

What is its final temperature?

At constant pressure a graph of volume V against kelvin temperature T is a straight line through the origin.

State the SI unit of its gradient.

At constant pressure a fixed mass of gas has a volume of 2.4 m³ at a temperature of 300 K.

The gas is heated until its temperature reaches 450 K.

Calculate the new volume of the gas.

A graph of pressure against 1/V for a gas at 17 °C has a gradient of 0.83 J.

Determine the number of gas molecules.

Two identical cylinders at the same temperature hold equal numbers of molecules: one of helium, one of nitrogen.

Which is correct?

State what is meant by one mole of a substance.

Calculate the number of moles of gas.

Samples of neon (molar mass 20 g mol⁻¹) and argon (40 g mol⁻¹) have the same pressure, volume and temperature.

What is (mass of neon) ÷ (mass of argon)?

0.20 mol of an ideal gas is at 1.2 × 10⁵ Pa in a volume of 5.0 × 10⁻³ m³.

Calculate its temperature.

A gas is kept at constant volume. It starts at 27 °C. Its pressure is then tripled.

What is its final temperature?

A fixed mass of gas has a volume of 8.0 L at a pressure of 250 kPa.

At the same temperature it is slowly compressed to a volume of 5.0 L.

Calculate the new pressure of the gas.

The end of a syringe is sealed and its plunger is pushed in rapidly.

What happens to the mean kinetic energy of the trapped air molecules, and why?

State what is meant by the absolute temperature of an ideal gas in terms of the motion of its particles.