A scientist investigates how the pressure and volume of a gas are related.
The results from their experiment are shown in the table.
| Pressure (kPa\text{kPa}kPa) | Volume (cm3\text{cm}^3cm3) |
|---|---|
| 200 | 600 |
| 300 | 400 |
| 500 | 240 |
| 800 | 150 |
| 1000 | 120 |
a.[2]
Explain how these results show that pressure×volume=constant\text{pressure} \times \text{volume} = \text{constant}pressure×volume=constant. Use calculations in your answer.
b.[1]
The graph shows the scientist's results, but one point is missing.
State the coordinates of the missing point that needs to be plotted on this graph.
c.[1]
Describe the line of best fit that should be drawn on the graph.
d.[2]
Calculate the volume of gas when the pressure is 600 kPa600\text{ kPa}600 kPa.
e.[2]
Explain how and why atmospheric pressure changes with height above the surface of the Earth.