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