Adewar bottle is a double-walled glass container whose interior has been made empty. these containers are generally used to conserve substances at very low temperatures
a) if the vacuum pressure is 1.00 pa, calculate the mean free path of the enclosed molecules between the walls of the dewar at a temperature of 220 k, taking an effective value of 0.4 nm2 for the cross section.
b) what is the frequency of collision between the molecules of this gas?
c) what is the purpose of the vacuum between the walls of this vessel?