Question

What is the work done by saturated water which evaporates to 10 kPa atmosphere to form 1 m^3 of water vapor?

(a) 1 kJ

(b) -1 kJ

(c) 10 kJ

(d) -10 kJ

The question was asked in an international level competition.

Enquiry is from Ideal Reversible Processes in chapter Energy Balances that Include the Effects of Chemical Reaction, Ideal Processes, Efficiency and the Mechanical Energy Balance and Heats of Solution and Mixing of Basic Chemical Engineering

Answer 1

Right option is (d) -10 kJ

The explanation is: Work done = -p∆V = -10*1 = -10 kJ.