Modes And Diffusion(Mass Transfer ) Questions and answers for exam Preparation

Question 1. The ratio of a mass concentration of species A to the total mass density of the mixture is known as

Mass density
Concentration
Mole fraction
Mass fraction

Explanation:-

Answer: Option D. -> Mass fraction
Answer: (d).Mass fraction

Question 2. A binary mixture of oxygen and nitrogen with partial pressures in the ratio 0.21 and 0.79 is contained in a vessel at 300 K. If the total pressure of the mixture is 1 * 10⁵ N/m², find molar concentration of oxygen.

8.42 * 10⁻¹ kg mol/m³
8.42 * 10⁻² kg mol/m³
8.42 * 10⁻³ kg mol/m³
8.42 * 10⁻⁴ kg mol/m³

Explanation:-

Answer: Option C. -> 8.42 * 10⁻³ kg mol/m³
Answer: (c).8.42 * 10⁻³ kg mol/m³

Question 3. For a binary mixture of species A and B, the molar average velocity is defined as

n ₐ V ₐ + n ᵦ V ᵦ
n ₐ V ₐ + nᵦ Vᵦ/n
n ₐ V ₐ + n ᵦ V ᵦ/2 n
n ₐ V ₐ + 2 n ᵦ V ᵦ/n

Explanation:-

Answer: Option B. -> n ₐ V ₐ + nᵦ Vᵦ/n
Answer: (b).n ₐ V ₐ + nᵦ Vᵦ/n

Question 4. The ratio of number of moles of species A to the total number of moles of the mixture is known as

Mole fraction
Mass fraction
Partial pressure
Mass density

Explanation:-

Answer: Option A. -> Mole fraction
Answer: (a).Mole fraction

Question 5. For a binary mixture of species A and B, the mass average velocity is defined as

2 pₐ Vₐ + pᵦ Vᵦ/ p
pₐ Vₐ + pᵦ Vᵦ/ p
pₐ Vₐ + 2 pᵦ Vᵦ/ p
pₐ Vₐ + pᵦ Vᵦ/ 2 p

Explanation:-

Answer: Option B. -> pₐ Vₐ + pᵦ Vᵦ/ p
Answer: (b).pₐ Vₐ + pᵦ Vᵦ/ p

Question 6. Which number forms the connecting link between the velocity and temperature profiles?

Fourier number
Prandtl number
Stanton number
Biot number

Explanation:-

Answer: Option B. -> Prandtl number
Answer: (b).Prandtl number

Question 7. Which number forms the connecting link between the velocity and concentration profiles?

Schmidt number
Reynolds number
Stanton number
Fourier number

Explanation:-

Answer: Option A. -> Schmidt number
Answer: (a).Schmidt number

Question 8. Which number forms the connecting link between the temperature and concentration profiles?

Prandtl number
Schmidt number
Fourier number
Lewis number

Explanation:-

Answer: Option D. -> Lewis number
Answer: (d).Lewis number

Question 9. What is the value of emissivity for polished aluminum?

0.01
0.02
0.03
0.04

Explanation:-

Answer: Option C. -> 0.03
Answer: (c).0.03

Question 10. Which one is having highest emissivity?

Tarnished copper
Polished aluminum
Aluminum foil
Polished copper

Explanation:-

Answer: Option A. -> Tarnished copper
Answer: (a).Tarnished copper