Consider 100 moles of a gas stream containing 15 mol% cs2, 18 mol% o2, and 67 mol% n2. the gas is fed to a continuous absorption tower, where it contacts liquid benzene, which absorbs cs2, but not o2 or n2. benzene is fed to a column in a 2: 1 mole ratio to the feed gas. some of the benzene entering as liquid evaporates and leaves the top of the tower as vapor. the gas leaving the absorber contains 2 mol% cs2 and 2 mol% benzene. how many independent material balances can you write?