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 1750 kg/h · 15% sugarStream 2700 kg/h · 40% sugarStream 3x₃ = ? %

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

ṁ1 = 750 kg/hx1 = 15 %ṁ2 = 700 kg/hx2 = 40 %
x3 = %
2.Easy
MixerStream 1950 kg/h · 20% saltStream 2500 kg/h · 10% saltStream 3x₃ = ? %

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

ṁ1 = 950 kg/hx1 = 20 %ṁ2 = 500 kg/hx2 = 10 %
x3 = %
3.Medium
MixerStream 1750 kg/h · 30% NaOHStream 2ṁ₂ = ? · 15% NaOHProduct20% NaOH

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

ṁ1 = 750 kg/hx1 = 30 %x2 = 15 %x3 = 20 %
ṁ2 = kg/h
4.Medium
MixerStream 1600 kg/h · 20% sugarStream 2ṁ₂ = ? · 40% sugarProduct30% sugar

How much of stream 2 must be added each hour to stream 1 so that the blended product contains 30% sugar? Find ṁ2.

ṁ1 = 600 kg/hx1 = 20 %x2 = 40 %x3 = 30 %
ṁ2 = kg/h
5.Hard
EvaporatorFeed F1300 kg/h · 10% saltProduct P50% saltVapour W (pure water)W = ? kg/h

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

F = 1300 kg/hxF = 10 %xP = 50 %
W = kg/h
6.Hard
EvaporatorFeed F2600 kg/h · 19% sugarProduct PP = ? · 40%Vapour W (pure water)0% sugar

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

F = 2600 kg/hxF = 19 %xP = 40 %
P = kg/h

Answer key

  1. 1. x3 = 27.07 %
  2. 2. x3 = 16.55 %
  3. 3. ṁ2 = 1500 kg/h
  4. 4. ṁ2 = 600 kg/h
  5. 5. W = 1040 kg/h
  6. 6. P = 1235 kg/h

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