Question

The vapor pressure of CCl3F at 300 K is 856 torr.

If 11.5 g of CCl3F is enclosed in a 1.1 L container, calculate the number of moles of CCl3F in the gas phase.

Answer 1

As per Ideal Gas Equation,

where P indicates the pressure of substance in gas phase

it is given, Vapour pressure of CCl₃F is 856 Torr=P

V is Volume, i.e, maximum volume that can be occupied by substance = 1.1 lit

n= number of moles of substance in gas phase

R = Universal gas constant =62.36357 L.Torr /mol K

T= Temperature = 300K

the number of moles in gas phase is 0.05 at 300K

The molecular weight of CCl₃F is 137.5

hence, 11.5 g of CCl₃F is

= 0.0836 moles

Hence, of this only 0.05 moles convert to gas state and remaining as liquid.