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Pure aniline is evaporating through a stagnant air film of 1 mm thickness at 300 K and a total pressure of 100 KPa. The vapor pressure of aniline at 300 K is 0.1 KPa. The total molar concentration under these conditions is 40.1 mole/m<sup>3</sup>. The diffusivity of aniline in air is 0.74 × 10<sup>-5</sup> m<sup>2</sup>/s. The numerical value of mass transfer co-efficient is 7.4 × 10<sup>-3</sup>. Its units are
A
m/s
B
cm/s
C
mole/m<sup>2</sup>.s.Pa
D
k.mole/m<sup>2</sup>.s.Pa
Correct Answer:
mole/m<sup>2</sup>.s.Pa
Pure aniline is evaporating through a stagnant air film of 1 mm thickness at 300 K and a total pressure of 100 KPa. The vapor pressure of aniline at 300 K is 0.1 KPa. The total molar concentration under these conditions is 40.1 mole/m
3
. The diffusivity of aniline in air is 0.74 × 10
-5
m
2
/s.The numerical value of mass transfer co-efficient is 7.4 × 10
-3
. The rate of evaporation of aniline is 2.97 × 10
-4
. Its units are
A
mole/s
B
mole/cm<sup>2</sup>.s
C
mole/m<sup>2</sup>.s
D
k.mole/m<sup>2</sup>.s
A stream of air at 100 kPa pressure and 300 K is flowing on the top surface of a thin flat sheet of solid naphthalene of length 0.2 m with a velocity of 20 m/sec. The other data are: Mass diffusivity of naphthalene vapor in air = 6 * 10 –6 m2/sec Kinematic viscosity of air = 1.5 * 10 –5 m2.sc Concentration of naphthalene at the air-solid naphthalene interface = 1 * 10 – 5 kmol/m3 Calculate the overage mass transfer coefficient over the flat plate. Note: For heat transfer over a flat plate, convective heat transfer coefficient for laminar flow can be calculated by the equation. Nu = 0.664 ReL1/2 Pr1/3 you may use analogy between mass and heat transfer.
A
0.014 m/sec
B
0.015 m/sec
C
0.016 m/sec
D
0.013 m/sec
Raw material purchased:
1
st
January, 600 units @ Rs. 12 per unit
12
th
January, 500 units @ Rs. 14 per unit
21
st
January, 300 units @ Rs. 13 per unit
Raw material issued for manufacture:
3
rd
January 300 units
5
th
January 124 units
15
th
January 250 units
16
th
January 300 units
Raw material returned to stores from manufacturing department on 14
th
January, 50 units. The material is issued on First-in-First out method.
The value of material remaining in store on 21
st
January will be:
A
5,775
B
6,100
C
6,350
D
6,600
In an accident a container containing ethanol(s.g 0.789) falls down in a room of dimension 1*1*2(all in m). Ethanol forms a layer of 2mm. Ethanol vaporizes and diffuses through a stagnant film of air of thickness 2.5mm. What will be the time required for the water layer to disappear completely. The diffusivity of ethanol in air is 2.567*10-5 m2/s. the total pressure is 1.013 bar and the pressure of ethanol in bulk air is 0.02244 bar and at the ethanol-air interface is 0.02718bar. The temperature is 25.2°C.
A
4.73h
B
14.6h
C
5.87h
D
16.2h
Only if the calculated molar mass is higher than the actual molar mass of the solute, the calculated molar mass is considered to be abnormal molar mass.
A
True
B
False
Oxygen diffuses through a stagnant layer of air, 1mm thick, ambient temperature 28°C and 1atm total pressure. The partial pressure of oxygen on two sides of layer is P1=0.9atm and P2=0.1atm respectively. Calculate the value of Molar flux (in mol/m2.s) with respect to an observer moving with molar average velocity. Calculate this value at the end of the path where P2=0.1atm. Use R=8.205*10-5m3atmK-1mol-1.
A
2.713
B
1.713
C
0.1713
D
0.01713
A passage is given with five questions following it. Read the passage carefully and select the best answer to each question out of the given fouralternatives. Just as space permeates everything in the universe, love permeates every part, every aspect of creation. If there is one answer to the question, “How and why doesthis world exist?” the answer, in one word, is Love. Rather, the answer is Pure Love, since the word love has lost its meaning. Your very existence is an expression of pure unconditional love of the Source (you may call it Consciousness, Creator, God, Divine Self). This is the truth of your being.True love transcends both love and hatred. It is unconditional, unquestioning, boundless, unchanging love. It is overflowing love of the Source for the Source throughall of creation. True love is way beyond the personalized love that two or more individuals assert on one another. Personalized love, though apparently selfless, is rooted in desiresand conditional satisfaction. We have been brought up in a society that judges love based on conditions. We have been made to believe that we can receive love only when we fit into peoplesexpectations. If we are not good enough, we will be deprived of love. These beliefs have influenced the collective psyche of families, groups, communities, and societies since generations to such an extent that love has been reduced tofear of denial. We need to shift from the paradigm of false conditional love to the essence of pure unconditional love . The experience of true love comes with surrender of the false I, in letting go of the feeling of separateness. Without this sacrifice, it is not possible to attain divinelove. When this separate I is discarded, you embrace everything in oneness and catch a glimpse of pure love. True love can be experienced only through giving, not by demanding. People who exist in your life are not here to love you. They are here to remind you that you arethe Source of Love. By knowing that you are the Source of love, you can love yourself, instead of waiting to receive love from the world. Ask yourself, “Why do I need an agent to love myself?” Waiting for the world to love you, is like hiring an agent to love yourself! It is time for you to honor yourself as the Source of love. You have undertaken this human journey to realize and express the boundless love that you truly are. Which of the following statement(s) is/are TRUE about pure love?
A
World exists not because of love but because of pure love.
B
Pure love is experienced with surrender of the false \u2018I\u2019.
C
It is experienced by giving and not by demanding something.
D
All of these
If ethanol and chloroform are present in a molar ratio of 2:3 then what is the vapor pressure at 20° C if vapor pressures of pure liquids are 5.95 kPa and 21.17 kPa, respectively?
A
16.692 kPa
B
15.082 kPa
C
8.731 kPa
D
12.038 kPa
For water at 300°C, it has a vapour pressure 8592.7 kPa and fugacity 6738.9 kPa Under these conditions, one mole of water in liquid phase has a volume of 25.28 cm
3
and that in vapour phase in 391.1 cm
3
. Fugacity of water (in kPa) at 9000 kPa will be
A
6738.9
B
6753.5
C
7058.3
D
9000
In a gas mixture of hydrogen and oxygen, steady state equimolar counter diffusion is occurring at a total pressure of 100 kPa and temperature of 20°C. If the partial pressures of oxygen at two planes 0.01 m apart, and perpendicular to the direction of diffusion are 15 kPa and 5 kPa, respectively and the mass diffusion flux of oxygen in the mixture is 1.6 * 10–5 kmol/m2.sec, calculate the molecular diffusivity for the system. For equimolar counter current diffusion:
A
2.898×10-5 m2/sec
B
3.898×10-5 m2/sec
C
2.989×10-5 m2/sec
D
3.989×10-5 m2/sec