Practseatworkems 7.1 A ideal gas occupies a volume of 100 cm at 20'C and 100 Pa. Find the number of moles of gas in the container. 7.2 A certain scuba tank is designed to hold 66 ft of air when it is at atmospheric pressure at 22 C. When this volume of air is compressed to an absolute pressure of 3000 Ib/in. and stored in a 10-L (0.35-fts) tank, the air becomes so hot that the tank must be allowed to cool before it can be used. (a) If the air does not cool, what is its temperature? (Assume that the air behaves like an ideal gas.)