A high-pressure diving cylinder is filled with a fixed mass of helium gas used for deep-sea diving.
Explain how the helium gas exerts a pressure on the interior walls of the diving cylinder. Refer to molecules in your answer.
Explain, in terms of helium molecules, what happens to the pressure of the helium gas inside the cylinder as its temperature is decreased.
A fixed mass of helium has a volume of 84 000 cm384\,000\text{ cm}^384000 cm3 when its pressure is 120 kPa120\text{ kPa}120 kPa.
Calculate the pressure of this fixed mass of helium when it is compressed inside the cylinder at a constant temperature.
[volume of helium in cylinder = 3500 cm33500\text{ cm}^33500 cm3]