The stream from a gas well is a mixture containing 50-mol-% methane. 10-mol-% ethane, 20-mol-% propane, and 20-mol-% n-butane. This stream is fed into a partial condenser maintained at a pressure of 250(psia). where its temperature is brought to 80(°F). Determine the molar fraction of the gas that condenses and the compositions of the liquid and vapor phases leaving the condenser.