A mixture of real gases is composed of 40 percent methane (CH4), 23 percent propane (C3H8), and 37 percent ethane (C2H6) by weight. This mixture is compressed from 0.93 MPa and 20 °C to 9.2 MPa in an isentropic, steady-flow compressor. Calculate the required work for this compression process per unit mass of the mixture by using generalized charts. Assume constant specific heats at 300 K.