This set of Basic Chemical Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Density”.

1. Which of the following is not a unit of density?

a) Kg/m^{3}

b) N/m^{3}

c) N.s^{2}/m^{4}

d) g/cm^{3}

View Answer

Explanation: Dimensions of density are M

^{1}L

^{-3}, which is not the dimension of N/m

^{3}, so N/m

^{3}is not the unit of density.

2. What is the density of a substance of mass 10 grams and volume 5 liters?

a) 2 kg/m^{3}

b) 20 kg/m^{3}

c) 200 kg/m^{3}

d) 2000 kg/m^{3}

View Answer

Explanation: Density = (10*10

^{-3})/(5*10

^{-3}) = 2 kg/m

^{3}.

3. A solid of density d is dropped in a liquid of density D, if d>D then,

a) Solid will completely sink

b) Solid will completely float

c) Solid will partially sink

d) None of the mentioned

View Answer

Explanation: Since density of solid is greater than that of liquid, this means that weight of the solid will be higher than its buoyancy force so it will completely sink.

4. A liquid of mass 10 kg is enclosed in a cylinder of radius 1 m and length 5 m, what is the density of liquid?

a) 0.54 kg/m^{3}

b) 0.44 kg/m^{3}

c) 0.63 kg/m^{3}

d) 0.83 kg/m^{3}

View Answer

Explanation: Volume of cylinder = π(1

^{2})5 = 5π m

^{3}, => Density = 10/5π = 0.63 kg/m

^{3}.

5. What is the density of a liquid of mass 20 kg, enclosed in a cuboid of surface areas of three sides as 1 m^{2}, 2 m^{2}, 5 m^{2}, and one of its sides is 2 m?

a) 1 kg/m^{3}

b) 2 kg/m^{3}

c) 3 kg/m^{3}

d) 4 kg/m^{3}

View Answer

Explanation: Sides of the cuboid are 1m, 2m and 5m, => volume = 10 m

^{3}, density = 20/10 = 2 kg/m

^{3}.

6. What is the density of a liquid of mass 10 kg and contained in a cylinder of radius 5 m and surface area (excluding top and bottom) of 10π m^{2}?

a) 0.2π kg/m^{3}

b) 0.4π kg/m^{3}

c) 0.5π kg/m^{3}

d) 0.6π kg/m^{3}

View Answer

Explanation: Height of cylinder = 10π/(2π*5) = 1 m, => volume of cylinder = π(5

^{2})1 = 25π, => density of liquid = 10/25π = 0.4π kg/m

^{3}.

7. What is the mass of a liquid having density 20 kg/m^{3}, enclosed in a sphere of radius 1 m?

a) 80.7 kg

b) 83.7 kg

c) 85.7 kg

d) 88.7 kg

View Answer

Explanation: Volume of liquid = (4/3)π1

^{3}= 4.18 m

^{3}, => mass of liquid = 20*4.18 = 83.7 kg.

8. What is the mass of a cube having surface area 24 m^{2}, and density 1 kg/m^{3}?

a) 1 kg

b) 2 kg

c) 4 kg

d) 8 kg

View Answer

Explanation: Side of the cube = (24/6)

^{0.5}= 2 m, => mass of cube = 1*2

^{3}= 8 kg.

9. An empty vessel has with mass 5 kg with volume 0.1 m^{3}, is now completely filled with a liquid of density 100 kg/m^{3}, what is the final density of the cylinder?

a) 50 kg/m^{3}

b) 100 kg/m^{3}

c) 150 kg/m^{3}

d) 200 kg/m^{3}

View Answer

Explanation: Mass of liquid = 100*0.1 = 10 kg, => total mass of cylinder = 10 + 5 = 15 kg, => final density of liquid = 15/0.1 = 150 kg/m

^{3}.

10. A cylinder completely filled with water has density = 10 kg/m^{3} and volume 5 m^{3} , now a cube with side 1 m and density 25 kg/m^{3} is dipped into the cylinder with some water dropping out, what is the final density of cylinder?(neglect the mass of cylinder)

a) 13 kg/m^{3}

b) 15 kg/m^{3}

c) 17 kg/m^{3}

d) 19 kg/m^{3}

View Answer

Explanation: Initial mass of cylinder = 10*5 = 50 kg, mass of cube = 25*1 = 25 kg, => mass of water coming out = 10*1 = 10 kg, => final density of cylinder = (50 + 25 – 10)/5 = 13 kg/m

^{3}.

**Sanfoundry Global Education & Learning Series – Basic Chemical Engineering.**

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