Question
(a) In terms of the momentum of molecules, explain how a gas exerts pressure on the walls of its container.
(b) A fixed mass of gas of volume \(V_1\) is at a pressure \(p_1\). It is compressed to a volume \(V_2\).
(i) Complete the equation for the final pressure \(p_2\) of the gas when the gas is compressed at constant temperature.
\(p_2\) =
(ii) State and explain how the final pressure compares with \(p_2\) when the temperature of the gas increases during compression.
statement
explanation
Answer/Explanation
Answer:
(a) molecules strike walls
momentum (of molecules) changes / momentum = mass× velocity
force = rate of change of momentum
pressure = (sum of) force(s) / area / pressure = rate of change of momentum / area
(b)(i) (\(p_2\)=)\(p_1\)\(V_1\) / \(V_2\) \(p_1\)\(V_1\) =\(p_2\)\(V_2\)
(ii) greater
molecules move faster / have greater KE / molecules have greater momentum
(leads to) more frequent / harder collisions (with walls) / great rate of change of momentum