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

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