STOICHIOMETRY CHEMISTRY

Question

A certain type of gas is found inside a polyethylene container with a pressure equivalent to 721.0 torr. If the

value of moles of the said gas is 12.01 moles, what would be the amount of pressure (in atm) inside the

container if there are 15.75 moles of gas in it?

Answer 1

Pressure is directly related to the number of moles of gas present when the temperature and volume are constant.

P1 = initial pressure = 721.0 torr

n1 = initial moles = 12.01 mols

P2 = final pressure = ?

n2 = final moles = 15.75 mols

From the combined gas law, we have....

P1/n1 = P2/n2

(721.0 torr) / 12.01 mols = P2 / 15.75 mols

P2 = (721)(15.75) / 12.01

P2 = 945.5 torr

Converting this to atmospheres, we have...

945.5 torr x 1 atm / 760 torr = 1.244 atm