(a)[1]
State what happens to the gas molecules in a sealed container when the gas temperature is raised.
(b)[2]
State, in terms of molecules, two reasons why the gas pressure rises.
(c(i))[2]
Calculate the new pressure of the helium. Assume the temperature remains constant.
(c(ii))[1]
Suggest why it may become necessary to release helium from the balloon as it rises further.