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 1500 kg/h · 15% sugarStream 2400 kg/h · 20% sugarStream 3x₃ = ? %

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

ṁ1 = 500 kg/hx1 = 15 %ṁ2 = 400 kg/hx2 = 20 %
x3 = %
2.Easy
MixerStream 1600 kg/h · 35% saltStream 2250 kg/h · 5% saltStream 3ṁ₃ = ? kg/h

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

ṁ1 = 600 kg/hx1 = 35 %ṁ2 = 250 kg/hx2 = 5 %
ṁ3 = kg/h
3.Medium
MixerStream 1550 kg/h · 30% saltStream 2ṁ₂ = ? · 15% saltProduct20% salt

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

ṁ1 = 550 kg/hx1 = 30 %x2 = 15 %x3 = 20 %
ṁ2 = kg/h
4.Medium
MixerStream 1250 kg/h · 10% sugarStream 2ṁ₂ = ? · 30% sugarProduct15% sugar

How much of stream 2 must be added each hour to stream 1 so that the blended product contains 15% sugar? Find ṁ2.

ṁ1 = 250 kg/hx1 = 10 %x2 = 30 %x3 = 15 %
ṁ2 = kg/h
5.Hard
EvaporatorFeed F2500 kg/h · 17% sugarProduct PP = ? · 65%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 = 2500 kg/hxF = 17 %xP = 65 %
P = kg/h
6.Hard
EvaporatorFeed F3400 kg/h · 12% saltProduct PP = ? · 55%Vapour W (pure water)0% salt

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

F = 3400 kg/hxF = 12 %xP = 55 %
P = kg/h

Answer key

  1. 1. x3 = 17.22 %
  2. 2. ṁ3 = 850 kg/h
  3. 3. ṁ2 = 1100 kg/h
  4. 4. ṁ2 = 83.33 kg/h
  5. 5. P = 653.8 kg/h
  6. 6. P = 741.8 kg/h

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