Keeping track of information with a table

One thousand kilograms per hour of a mixture of benzene (B) and toluene(T) that contains 50% benzene by mass are seperated by distillation into two fractions. The mass flow rate of benzene in the top stream is 450 kg B/h, and that of toluene in the bottom stream is 475 kg T/h. The operation is at steady state. Write balances on benzene and toluene to calculate the unknown component flow rates in the output streams.

F_{total, toluene} = F_{bottoms, toluene} + F_{bottoms,toluene}

500 = F_{overhead, toluene} + 475

F_{overhead, toluene} = 500 - 475 = 25 kg/h.

We now know everything that we can know about this process. We must be able to answer any of the questions that they ask us.

Streams\mass flow rate	Total	Benzene	Toluene
Feed	1000	500	500
Overhead	475	450	25
Bottoms	525	50	475