Practice Exams ChE - 33

1. Pig iron is product in a blast furnace from hematic ore containing 80% Fe2O3. The pig iron produced is 96% Fe. The slag contains 10% of iron present in the ore. How many tons of pig iron produced per 500 tons of ore?
a. 450
b. 156
c. 353
d. 272
e. none of these

2. If pressure on the fluid in the reaction line drops, some liquids flashes into vapor. This flashing is called
a. diffusion
b. vaporization
c. boiling
d. cavitation
e. none of the above

3. A glass sphere having a diameter at 1.554 x 10^-4 m in water at 293.2 K and the slurry contains 60% wt. solids. The density of the glass sphere is 2467 kg/m^3. The settling velocity of the glass sphere is
a. 3.05 x 10^-3 m/s
b. 0.205 m/s
c. 1.525 x 10^-3 m/s
d. 5.125 x 10^-4 m/s
e. none of the above

4. A solution is prepared at 20 degC containing 7.8% wt. benzene in non-soluble oil (MW =922). Vapor pressure of benzene at 20 degC is 75 mm Hg. What is the equilibrium pressure of benzene vapor in mm Hg above the solution?

5.
a. Allosteric enzymes
b. Isoenzymes
c. Identical enzymes
d. Endoenzymes
e. Exoenzymes are represented with sigmoidal curves.

6. Humid air at temperature 600 degF and a total pressure of 1 atm passed through a dehumidifier at the rate of 1000 cfm. If the partial pressure of water vapor in air is reduced from 44 mmHg to 10 mmHg. How many pounds of water are removed per hour?
a. 81.4
b. 65.2
c. 45.4
d. 76.3
e. none of these

7. ___________ is normally used to determine the quality of combustion gases.
a. Stoichiometry
b. Orsat analysis
c. Gravimetric analysis
d. Material Balance
e. None of these

8. The greater the surface area of the packing of the fractionating or absorption column,
a. the greater the efficiency
b. the lower its efficiency
c. efficiency does not depend on the surface area of the column
d. the faster the distillation will proceed
e. none of these

9. The pipe size of a pneumatic conveyor to convey plastic pellets with bulk density of 30 lb/ft^3 using a blower with a capacity of 600 ft^3/min is ____ inches.
a. 3
b. 5
c. 8
d. 2
e. none of these

10. A furnace has an area of 1000 ft^2 exposed to the surroundings. The furnace is made of 6 inch thick insulating bricks with a thermal conductivity of 0.15 Btu/h-ft^2(F/ft). The change in temperature across the brick is 150 degF. How much fuel is required in lb/day t heat the furnace if the fuel has a heating value of 15,000 Btu/lb?
a. 342
b. 26
c. 72
d. 610
e. none of these