B. A gas containing 88% (by volume) CH4, 4%C2H6, 5% n-C3H8, and 3% n-C4H10 at 300 K and 500 kPa will be scrubbed by contact with a nonvolatile oil in a gas absorber. The objective of the process is to recover in the liquid effluent as much as possible of the heavier hydrocarbons in the feed (Figure 4). Calculate: (a) Total molar concentration in the gas feed. (b) Density of the gas feed. (c) Composition of the gas feed, expressed in terms of mass fractions. Nonvolatile oil Scrubbed gas Gas absorber Liquid product Gas feed 300 K, 500 kPa Figure 4: Schematic diagram of gas absorber. Source: Benitez, 2016