CC&HT Flashcards
(30 cards)
A chemical process is said to occur under steady state, if the:
A. Flow rates & composition both are time dependent
B. Inventory changes do not take place
C. Ratio of streams entering/leaving are independent of time
D. All of these
E. None of these
Flow rates & composition both are time dependent
A rocket engines burns a stoichiometric mixture of fuel in oxidant. The combustion
chamber is cylindrical, 85 cm long and 50 cm in diameter, and the combustion
process produces 108 kg/s of exhaust gases. If combustion is complete, find the rate
of reaction of oxygen.
1.7975 x 10^4
Arrange the following coals according to their rank.
A. Bituminous, Anthracite, Sub-bituminous, Lignite
B. Anthracite, Bituminous, Sub-bituminous, Lignite
C. Anthracite, Bituminous, Lignite, Sub-bituminous
D. Lignite, Anthracite, Bituminous, Sub-bituminous
Anthracite, Bituminous, Sub-bituminous, Lignite
A petroleum distillate having flash point not below 22.8oC as determined by the
Abel Tester.
A. Kerosene
B. Gasoline
C. Diesel
D. LPG
Kerosene
The boiling points for pure water and pure toluene are 100oC and 110.6oC
respectively. Toluene and water are completely immiscible in each other. A well
agitated equimolar mixture of toluene and water are prepared. The temperature at
which the above mixture will exert a pressure of one standard atm is
Between 100 and 110oC
The reaction A + B = C has been conducted in a reactor as shown below. The
number of balances (material) that can be made around the reactor are
3
The reactor A = 2B + C takes place in a catalytic reactor. The reactor effluent
is sent to a separator. The overall conversion of A is 95%. Leaving the separator is the product and the recycle stream. The product from the separator consists of B, C
and 0.5% of A entering the separator, while the recycle stream consists of the
remainder of the unreacted A and 1% of B entering the separator. Calculate the single pass conversion of A:
NOTA
the product and the recycle stream. The product from the separator consists of B, C
and 0.5% of A entering the separator, while the recycle stream consists of the
remainder of the unreacted A and 1% of B entering the separator. Molal ration of recycle to feed is:
NOTA
A solvent recovery system delivers a gas saturated with benzene vapor that analyzes
on a benzene free basis as follows: 15% CO2, 4% O2, 81% N2. This gas is at 21oC
and 750 mmHg. It is compressed to 5 atm and cooled to 21oC after compression.
How many kg of benzene are condensed by this process per 1000 m3 of the original
mixture? VP of benzene at 21oC is 75 mmHg.
NOTA
Calcium hypochlorite is produced by absorbing chlorine in a milk of lime. A gas
produced by the deacon process is fed to an absorption column at 100 kPa and 20oC.
The partial pressure of chlorine is 8.266 kPa, the remainder being inert gases. The
gas leaves the column at 29.5oC and 99.3 kPa with chlorine partial pressure of 0.093
kPa. Calculate the volume of gases leaving the absorption column per 100m3 entering.
NOTA
Calcium hypochlorite is produced by absorbing chlorine in a milk of lime. A gas
produced by the deacon process is fed to an absorption column at 100 kPa and 20oC.
The partial pressure of chlorine is 8.266 kPa, the remainder being inert gases. The
gas leaves the column at 29.5oC and 99.3 kPa with chlorine partial pressure of 0.093
kPa. Weight (kg) of chlorine gas absorbed per 100 m3 entering:
NOTA
The ratio of % total carbon obtained in the ultimate analysis of coke and % fixed
carbon obtained in the proximate analysis is always
> 1
The vapor pressure of the solvent decreased by 10 mmHg, when a non-volatile
solute was added to the solvent. The mole fraction of the solute in the solution is
0.2. What should be the mole fraction of the solvent if the decrease in vapor
pressure of the solvent is required to be 20 mmHg?
0.6
Pick out the wrong statement.
A. To make 100 kg of a solution containing 40% salt by mixing solution A (containing 50% salt), the amount of solution A required is 40 kg.
B. 1.2 g atoms of carbon and 1.5 g moles of oxygen are reacted to give 1 g mole of carbon dioxide. The limiting reactant is carbon. The percent excess supplied is 25.
C. A gas bubble at a pressure of Pg is passed through a solvent with a saturation vapor pressure of Ps. If the time of passage of the bubble is long and air is insoluble in the solvent, the mole fraction of solvent in the bubble will be equal to Ps/Pg.
D. A supersaturated solution of a sparingly soluble solute, at a concentration of C, is being fed to a crystallizer at a volumetric flow rate of V. The solubility of the solute is C1. The output rate of solids from an efficient crystallizer is (C + C1) V.
A supersaturated solution of a sparingly soluble solute, at a concentration of C, is being fed to a crystallizer at a volumetric flow rate of V. The solubility of the solute is C1. The output rate of solids from an efficient crystallizer is (C + C1) V.
N2 content in a urea sample was found to be only 42%. What is the actual urea
content of the sample?
90%
A bypass stream in a chemical process is useful, because it
Facilitates better control
The wall of a furnace is constructed from a 0.15 m thick brick having a thermal
conductivity of 1.7 W/m-K. At steady state, the temperatures of the inner and the
outer surfaces are 2060oF and 1610oF respectively. What is the rate of heat loss
through a wall that is 0.5 by 1.2 m on a side?
1700 W
If the critical radius of insulation is greater than the pipe radius, then adding more
layers of insulation
A. Will not have any further on the heat transfer rate
B. Will increase heat transfer rate
C. Will decrease heat transfer rate
D. Will stop heat transfer
Will increase the heat transfer
Important in unsteady state heat transfer, this dimensionless number is defined as the ratio of boundary layer surface resistance to convection and internal resistance to conduction.
A. Biot Number
B. Fourier Number
C. Stanton Number
D. Prandtl Number
Biot NUmber
The temperature of a 0.012 m thick slab made of a hard rubbery material and
originally at 26.7oC is to be raised to 132.2oC. The thermal diffusivity of the slab �
�= 3.0 x 10-7 m2/s, k = 0.20 W/m-K, and h = 5.7 W/m2-K. The surrounding fluid
temperature is 141.7oC. Determine the Biot number
0.342
The temperature of a 0.012 m thick slab made of a hard rubbery material and
originally at 26.7oC is to be raised to 132.2oC. The thermal diffusivity of the slab �
�= 3.0 x 10-7 m2/s, k = 0.20 W/m-K, and h = 5.7 W/m2-K. The surrounding fluid
temperature is 141.7oC. Determine the Fourier number.
NOTA
The temperature of a 0.012 m thick slab made of a hard rubbery material and
originally at 26.7oC is to be raised to 132.2oC. The thermal diffusivity of the slab �
�= 3.0 x 10-7 m2/s, k = 0.20 W/m-K, and h = 5.7 W/m2-K. The surrounding fluid
temperature is 141.7oC. Determine the time needed to achieve the temperature change needed.
59.3
A large block of steel with k = 45 W/m-K and α = 4 x 10-5 m2/s is initially at a uniform temperature of 35oC. The surface is exposed to a heat flux by suddenly raising the temperature to 200oC. Calculate the temperature at a depth of 3 cm after 20 s
110 degrees celsius
A gray body is where
A. Absorptivity is a function of wavelength and is less than 1.
B. Absorptivity is a function of wavelength and is equal to 1.
C. Absorptivity is not a function of wavelength and is equal to 1.
D. Absorptivity is not a function of wavelength and is less than 1.
Absorptivity is not a function of wavelength and is less than 1
