A mixture of carbon dioxide (40 mol %), methane (40 mol %) and n-butane (20 mol %) at 300°C and 1 bar is compressed to compressed to 25 bar in a compressor that has an isentropic efficiency of 85%. The exiting stream is then adiabatically expanded through a Joule-Thompson expansion valve to 3 bar.

a. How much work is required in the compressor and what is the temperature of the exiting stream? 

b. What is the temperature of the streams leaving the expansion valve, what are the relative amounts of the vapor and liquid streams, and what are their compositions?