# Question 4

4.1 Charles’ Law describes the relationship between the volume and temperature
of an enclosed mass of gas at constant pressure. The volumes of a gas at
different temperatures at constant pressure are given in the table below.

4.1.1 Explain Charles’ Law in terms of the kinetic molecular theory
of gases. (2)

4.1.2 Draw a graph of volume versus temperature at constant pressure on
the attached graph paper. (4)

4.1.3 Extrapolate the graph (extend the graph) and state at what
temperature the graph intersects the x-axis. (1)

4.1.5 Calculate the volume that this gas will occupy at 120 °C at constant
pressure. (3)

4.1.6 The experiment is now conducted at a lower constant pressure.
On the graph drawn for QUESTION 4.1.2, sketch the graph that will
be obtained at a lower pressure. Label this graph P. (2)

4.2 An unknown gas with a mass of 0,77 g occupies a volume of 0,32 dm3 at
a temperature of 27 °C and a pressure of 96 kPa. Assume that the gas
behaves as an ideal gas.

4.2.1 Calculate the molar mass of the gas. (5)

4.2.2 Write down the MOLECULAR FORMULA or NAME of the gas
named in QUESTION 4.2.1. (2)
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