Mass balance worksheet with answers

Free printable Mass balance worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

New worksheetPractise online with hints

For teachers: free to print, copy and use in class. Every new worksheet has new values and its own answer key. A link to ExamProblems on your course page is appreciated.

Name: ____________________   Date: ____________

1.Easy
MixerStream 1250 kg/h · 30% sugarStream 2700 kg/h · 10% sugarStream 3ṁ₃ = ? kg/h

Two sugar solutions are mixed at steady state. Find the outlet flow rate ṁ3.

ṁ1 = 250 kg/hx1 = 30 %ṁ2 = 700 kg/hx2 = 10 %
ṁ3 = kg/h
2.Easy
MixerStream 1650 kg/h · 35% NaOHStream 2450 kg/h · 20% NaOHStream 3ṁ₃ = ? kg/h

Two NaOH solutions are mixed at steady state. Find the outlet flow rate ṁ3.

ṁ1 = 650 kg/hx1 = 35 %ṁ2 = 450 kg/hx2 = 20 %
ṁ3 = kg/h
3.Medium
MixerStream 1400 kg/h · 20% sugarStream 2ṁ₂ = ? · 40% sugarProduct35% sugar

How much of stream 2 must be added each hour to stream 1 so that the blended product contains 35% sugar? Find ṁ2.

ṁ1 = 400 kg/hx1 = 20 %x2 = 40 %x3 = 35 %
ṁ2 = kg/h
4.Medium
MixerStream 1300 kg/h · 10% NaOHStream 2ṁ₂ = ? · 40% NaOHProduct25% NaOH

How much of stream 2 must be added each hour to stream 1 so that the blended product contains 25% NaOH? Find ṁ2.

ṁ1 = 300 kg/hx1 = 10 %x2 = 40 %x3 = 25 %
ṁ2 = kg/h
5.Hard
EvaporatorFeed F900 kg/h · 11% NaOHProduct P55% NaOHVapour W (pure water)W = ? kg/h

An evaporator concentrates a NaOH solution by boiling off pure water. Find the water evaporated W in kg/h.

F = 900 kg/hxF = 11 %xP = 55 %
W = kg/h
6.Hard
EvaporatorFeed F2300 kg/h · 10% NaOHProduct PP = ? · 30%Vapour W (pure water)0% NaOH

An evaporator concentrates a NaOH solution by boiling off pure water. Find the product flow P in kg/h.

F = 2300 kg/hxF = 10 %xP = 30 %
P = kg/h

Answer key

  1. 1. ṁ3 = 950 kg/h
  2. 2. ṁ3 = 1100 kg/h
  3. 3. ṁ2 = 1200 kg/h
  4. 4. ṁ2 = 300 kg/h
  5. 5. W = 720 kg/h
  6. 6. P = 766.7 kg/h

Full step-by-step solutions: practise this topic on examproblems.com.