Moles to Volume Conversion

- At specific pressure and temperature one mole of any gas occupies the same volume.
- At 0 degrees C and 101.3 kPA
1 mole = 22.4 L
- This temperature is called STP

-- 22.4 L/mol is the molar volume as STP

Examples:

- How many litres will 3.5 Cl(g) occupy at STP?

3.5 mol x  22.4 L = 78.4 L
                1 mol
( because there is only 2 significant digits the answer becomes 78 L )

- A certain gas is found to occupy 12.3 L at STP. How many moles of gas is there?

12.3 L x  1 mol    =   0.549 mol
               22.4 L

- At STP an unknown gas is found to occupy 150mL. How many moles of gas must be there?
    1L = 1000mL
150 mL x   1 mol     = 6.6964 mol
                 22.4 mL  
6.6964 mL             
  1000                          = 0.0670 mol

*** remember you must convert your mL to L. Doesn't matter if you do it first or last!
      
Nicole H