Calculate the amount in moles of a gas which occupies 250cm3 at s.t.p

0.01 moles (I am guessing)

Explanation:

Firstly, cm3 and ml are equal to one another, therefore 250cm3 can also be written as 250 ml. I Googled and found that ideally, one mole of gas will occupy a volume of 22.4 L (22,400 ml) at s.t.p. 250 ml out of 22,400 ml is 0.01 rounded, therefore I assume that is the answer. About 0.01 mole occupies 250 cm3 at s.t.p.

It should be neon and argon I think..