State the equation that connects pressure and volume of a fixed mass of gas at constant temperature.

Complete the table to show the meanings of the symbols in this equation and their units.

What would happen to the pressure of a gas if it was squeezed into a smaller volume?

A cylinder contains $400 {\mathrm{cm}}^3$ of air at a pressure of $2\times {10}^5 \mathrm{Pa}$. The air is compressed to a volume of $160 {\mathrm{cm}}^3$.
Calculate the pressure when the air has returned to its original temperature.

Compressing a gas generally increases its temperature. If the pressure of the air is squeezed into less volume had been measured before it had returned to its original temperature, state whether it have been greater than or less than your calculated value. Explain your answer.

A mass of gas is at $40°\mathrm{C}$ and a pressure of $200 \mathrm{kPa}$. It occupies a volume of $100 {\mathrm{cm}}^3$. The gas is compressed slowly, so that the temperature does not change. Calculate the new volume when the pressure is $500 \mathrm{kPa}$.