Moles to Volume Conversions

  Some important facts to remember when converting from moles to volume are:

-At a specific pressure and temperature, 1 mol of gas occupies the same volume.

-> At 0º C and 101.3 kPa, 1 mol = 22.4 L

  Therefore, the number of atoms there are of a gas is irrelevant in converting as every gas will occupy the same volume. STP, or Standard Temperature and Pressure is another more convenient way to refer to 0ºC & 101.3 kPa. At STP, 22.4 L/mol is molar volume.

EXAMPLE:

  How many litres exist in 3.5 mol of Oxygen (O2)?

1. Write out what you know and what you want to find out.

2.5 mol   x   22.4 L   =  ?  L

     1 mol

2. Cancel out what you can and solve accordingly.

2.5 mol   x   22.4 L   =   56 L

  1 mol

*ALWAYS REMEMBER TO PUT THE APPROPRIATE NUMBER OF SIGNIFICANT DIGITS

EXAMPLE:

  Chlorine (Cl2) occupies 240 mL. How many moles exist?

1. Convert mL to L.

240 mL   x   1 L   =   0.240 L

 1000 mL

2. Write what you know and what you want to find out.

0.240 L   x   1 mol   =   ? mol

   22.4 L

3. Cancel out what you can and solve accordingly.

0.240 L   x   1 mol   = 0.0107 mol

22.4 L

*ALWAYS REMEMBER TO PUT THE APPROPRIATE NUMBER OF SIGNIFICANT DIGITS

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