Molar Volume

Molar Volume
-Molar volume of a gas at STP gases expand and contract with changes in temperature and pressure.
-We have a standard condition to compare volume of gases called STP(Standard Temperature Pressure)

•            STP = 1 atmosphere at pressure and a temp at 0 degrees celsius or 273.15K
•            At STP 1 mole of gas occupies 22.4L, thus we can create the conversion factors 
• 22.4L/mole of gas  OR mole of gas/22.4L

EXAMPLE

Calculate the volume occupied by 3.4g of ammonia at STP.

SOLUTION

Molar mass of ammonia (NH^3) = (1x14) + (3x1) = 173 mol - - - - - - moles of ammonia = 3.4 g x 1 mole / 17g

Molar volume = 22.4L
                       = 0.2 moles x 22.4L/mole
                       = 4.5L
Volume of occupied by 3.4 g of ammonia at STP = 4.5L