An oceanographer investigates the relationship between the pressure and volume of a fixed mass of air trapped in a flexible sampling chamber of an underwater drone at a constant temperature.
She records the volume of the gas chamber as she increases the depth (thereby increasing the pressure, loading) and as she brings the drone back to the surface (decreasing the pressure, unloading).
Her results are shown in the table below:
| Pressure (kPa\text{kPa}kPa) | Volume of gas (loading) (cm3\text{cm}^3cm3) | Volume of gas (unloading) (cm3\text{cm}^3cm3) | Average (mean) volume (cm3\text{cm}^3cm3) |
|---|---|---|---|
| 240 | 49.0 | 51.0 | 50.0 |
| 200 | 58.0 | 61.0 | 59.5 |
| 160 | 73.0 | [missing] | 74.5 |
| 120 | 99.0 | 102.0 | 100.5 |
| 100 | 119.0 | 122.0 | 120.5 |
Calculate the missing unloading volume of gas at a pressure of 160 kPa160\text{ kPa}160 kPa.
Suggest one reason why the oceanographer takes readings whilst pressure is both increasing and decreasing.
The oceanographer concludes that her data validates Boyle's Law (p×V=constantp \times V = \text{constant}p×V=constant) for a fixed mass of gas.
Show calculations for at least three different pressures to evaluate whether the data supports her conclusion.
