Question

A conical flask has a volume of 71.9 mL. It is filled with water vapour at a pressure of 1053.8 kPa and a temperature of 738 K. Determine the mass of
water in the conical flask.
Select one:
O a. 0.363 g
O b.0.183 g
O c.0.129 g
O d. 0.222 g​

Answer 1

Answer:

d. 0.222 g​

Explanation:

Given parameters:

volume of water  = 71.9mL  = 0.0719L

pressure  = 1053.8kPa = 10.4atm

temperature  = 738K

Unknown:

mass of water  = ?

Solution:

To find the mass of water, we need to obtain the number of moles from the given parameters.

This can be done using the ideal gas law;

              PV  = nRT

where P is the pressure

          V is the volume

           n is the number of moles

           R is the gas constant

           T is the temperature

     Input the parameters to find n;

          10.4 x 0.0719  = n x 0.082 x 738

                  n  = 0.012moles

Mass of water vapor  = number of moles x molar mass

          molar mass of H₂O  = 2 + 16  = 18g/mol

Mass of water vapor  = 0.012 x 18 = 0.22g