What is the volume of 4.92 grams of hydrogen gas at STP? (Show the work using dimensional analysis)

The volume of 4.92 grams of hydrogen gas at STP is 55 L.

Explanation:

1  mole of an ideal gas will occupy  22.4 L

To find volume, the molar volume of a gas is

22.4 L /  1 mole H 2  →  this takes you from moles of  H 2  to liters

Now, to find the number of moles present in  4.92 g  of hydrogen gas, you can use the gas' molar mass

 4.92  g   1 mole H 2  / 2.016 g  =  2.44 moles H 2

This sample of hydrogen gas will thus occupy

2.44  moles H 2   22.4 L  / 1  mole H 2  =  54.6 L  = 55 L.