Chlorine is used to disinfect drink water supplies and pool water. Suppose you have 17.3 L of Cl2 in a cylinder at 1200 torr and 24 C. How many grams of chlorine do you have in the gas cylinder?

Use PV = nRT

with P in atmospheres and T in Kelvin, solve for n.
Then moles = n = grams/molar mass and solve for grams.