1.1. Figure 16 shows a metal container with a movable piston.

Figure 16

Point X is on the inner surface of the container. The gas in the container is at a higher pressure than the air outside the container.

Which of these shows the direction of the force, due to the gas, on the container at point X?

1.2. The pressure of the gas in Figure 16 (P₁) is 120 kPa.

The volume of the gas in Figure 16 (V₁) is 2500 cm³ The piston is pushed up slowly so that the temperature of the gas does not change.

The new volume of the gas (V₂) is 1600 cm³.

Calculate the new pressure of the gas, P₂. Use the equation

${P}_{2}=\frac{{P}_{1}\times{V}_{1}}{{V}_{2}}$

new pressure, P₂= ................................. kPa

1.3. Figure 17 shows a bicycle pump with a closed end.

Figure 17

The area of the piston is 2 cm².

A force of 28 N is applied to the piston.

Calculate the pressure, in N/cm², of the piston on the air in the bicycle pump.

pressure = .............................................. N/cm²

1.4. A container is sealed so that the mass of the gas inside cannot change.

The volume of the gas is changed and the pressure is measured at different volumes.

The temperature of the gas does not change. Figure 18 is a graph of the results.

Figure 18

Explain, in terms of the movement of particles, why there is a pressure on the container and why the pressure changes as shown in Figure 18.