# Given that 0.28 g of dry gas occupies a volume of 354 mL at a temperature of 20°C and a pressure of 686 mmHg, how do you calculate the molecular weight of the gas?

##### 1 Answer

May 14, 2018

#### Answer:

#### Explanation:

- We start with the Ideal Gas Law equation
#PV# =#nRT# - Rearrange the equation to
#n/V# =#P/(RT)# - Convert the
#20^@C# to Kelvin#(K)# by adding#273#

- Plug into the equation

- Multiply
#62.36367# by#293# then divide by#686#

- Convert
#354mL# to#L# by dividing#354mL# by#1000# - Now calculate the density
#d# =#M/V#

- Take the
#g/L# and divide by#(mol)/L#