Physics 9702/51 — October/November 2018

A student is investigating how the boiling point of a salt solution varies with pressure.

It is suggested that the relationship between the Celsius temperature $\theta$ at which the water of the solution starts to boil and the air pressure $P$ is

where $\sigma$ is the density of the solution and $k$ and $q$ are constants.

Design a laboratory experiment to test the relationship between $\theta$ and $P$.
Explain how your results could be used to determine values for $k$ and $q$.

You should draw a diagram, on page 3, showing the arrangement of your equipment. In your account you should pay particular attention to

• the procedure to be followed,
• the measurements to be taken,
• the control of variables,
• the analysis of the data,
• any safety precautions to be taken.