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 1150 kg/h · 40% sugarStream 2700 kg/h · 10% sugarStream 3x₃ = ? %

Two sugar solutions are mixed at steady state. Find the mass fraction of sugar in the outlet x3.

ṁ1 = 150 kg/hx1 = 40 %ṁ2 = 700 kg/hx2 = 10 %
x3 = %
2.Easy
MixerStream 1750 kg/h · 40% NaOHStream 2600 kg/h · 20% NaOHStream 3ṁ₃ = ? kg/h

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

ṁ1 = 750 kg/hx1 = 40 %ṁ2 = 600 kg/hx2 = 20 %
ṁ3 = kg/h
3.Medium
MixerStream 1700 kg/h · 50% sugarStream 2ṁ₂ = ? · 20% sugarProduct40% sugar

How much of stream 2 must be added each hour to stream 1 so that the blended product contains 40% sugar? Find ṁ2.

ṁ1 = 700 kg/hx1 = 50 %x2 = 20 %x3 = 40 %
ṁ2 = kg/h
4.Medium
MixerStream 1900 kg/h · 30% sugarStream 2ṁ₂ = ? · 15% sugarProduct20% sugar

How much of stream 2 must be added each hour to stream 1 so that the blended product contains 20% sugar? Find ṁ2.

ṁ1 = 900 kg/hx1 = 30 %x2 = 15 %x3 = 20 %
ṁ2 = kg/h
5.Hard
EvaporatorFeed F2600 kg/h · 17% NaOHProduct PP = ? · 50%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 = 2600 kg/hxF = 17 %xP = 50 %
P = kg/h
6.Hard
EvaporatorFeed F4500 kg/h · 11% NaOHProduct P45% 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 = 4500 kg/hxF = 11 %xP = 45 %
W = kg/h

Answer key

  1. 1. x3 = 15.29 %
  2. 2. ṁ3 = 1350 kg/h
  3. 3. ṁ2 = 350 kg/h
  4. 4. ṁ2 = 1800 kg/h
  5. 5. P = 884 kg/h
  6. 6. W = 3400 kg/h

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