Question

3- 1 mole of liquid benzene is in equilibrium with 1 mole of gaseous benzene at 80.1 oC in a isolated piston at 1.00 atm. Suppose the pressure of the piston is increased to 2.00 and kept constant, and no heat flows in and out of the system. What will be the final composition, volume, and the temperature inside the piston? Assume perfect gas behavior for the gas and molar volume of the liquid benzene (90.0 cm3/mol) does not change significantly in this pressure range.

Answer 1

This question is related to thermodynamics.

Benzene has a light yellow color and it is a liquid.

Benzene is flammable with a petroleum like and it has aromatic odour.

Benzene liquid has less density than water and that's why it floats on water. Whereas ;

Benzene vapors are heavier than air.

1 mol of liquid benzene is in equilibrium with 1 mol of gaseous benzene at 80 degree Celsius in a piston at 1 atmospheric pressure Which means that tha 80 degree Celsius is the boiling point of benzene.

When pressure is increased upto 2 atm, then no heat flow occurs from system to surrounding and from surrounding to system which means that the system is adiabatic where no heat change from out to In occurs.

As we know from the ideal gas equation that,

PV = nRT,

pressure is directly proportional to temperature.

As pressure will be increase, the temperature will also increase inside the piston. With increasing In temperature , the gaseous benzene starts convert into liquid benzene because of compression process And the total composition will change towards the liquid benzene.

The whole volume inside the piston will remain same , only gaseous particles will change into liquid form. Due to which the amount of liquid particles will increase and the amount of gaseous particles become decreases But the whole volume inside the piston remain same.