Answer to Question #115022 in General Chemistry for Dr. Joe

Question

What is the volume of a gas at STP if it occupied a volume of 45 mL at 0.75 atm and 21⁰C?

Answer 1

We have Mendeleyev's formula: $pV=nRT$ .

From this, we find: $n=pV/RT$ = 0.75*0.045/0.082*294=0.0014 mole

On STP, 1 mole of gase is 22.4l

V=0.0014mole*22.4l=0.031l=31mL

Answer is 31 mL