State what is meant by a mole.
Two containers A and B are joined by a tube of negligible volume, as illustrated in the figure below.
The containers are filled with an ideal gas at a pressure of 
. The gas in container A has volume 
and is at a temperature of 
. The gas in container B has volume 
and is at a temperature of 
. Calculate the total amount of gas, in 
, in the containers.
