Question

A 125 mL flask contains 75 kPa Cl2 at 22 ˚C.

(a) How many moles of Cl2 are in the flask?
(b) What mass of Cl2 is in the flask?

Answer 1

1 mole at those conditions would occupy 32.7L
So, you must have 0.125/32.7 = 0.0038 moles
now multiply that by 35.5 g/mole