10 moles of oxygen divides and enters two reactors flow rate 45 kg/s and leaves the reactors at the flow rates of 6 kg/s and 9 kg/s, what are number of moles of oxygen that leaves the reactor with 9 kg/s?

Correct Answer:
Let number of moles entering and leaving the second reactor be n1 and n2 respectively, applying reaction equilibrium equation to whole system, => 10*45 = n*(6 + 9), => n = 30, => Applying reaction equilibrium equation to both the reactors separately, => n1*45 = n2*9 => n2 = 5n1, and (10 – n1)*45 = (30 – n2)*6, Solving both equations we get n2 = 90.