Chapter 19 - Work, Heat, and the First Law of Thermodynamics - Exercises and Problems - Page 543: 1

The work done on the gas is -80 J

We can calculate the work done on the gas as: $W = -P\Delta V$ $W = -P ~(V_f-V_i)$ $W = -(4.00\times 10^5~Pa)(300\times 10^{-6}~m^3-100\times 10^{-6}~m^3)$ $W = -80~J$ The work done on the gas is -80 J.