Practice Exams ChE - 32

1. A gaseous mixture containing 50% mol H2 and 50% mol acetaldehyde is initially contained in a rigid vessel at 1 atm. The formation of ethanol occurs. After a time, it was noted hat the pressure had dropped to 700 mmHg. Calculate the degree of completion of the reaction.
a. 15.8%
b. 17.2%
c. 7.8%
d. 9.2%
e. none of the above

2. In rebuilding a heat exchanger, the 12 BWG copper tubes are being replaced by aluminum tubes. To provide equal heat transfer rate after the rebuilding of the heat exchanger, what should be the thickness of the aluminum in inches, if the outer diameter is maintained at 2 inches? Note: Use the properties of materials at 100 degC.
a. 0.085
b. 2.062
c. 0.109
d. 0.153
e. none of the above

3. A three effect evaporator uses original steam at a saturation pressure of 174.4 kPa gage. The total boiling point rise is 8.3 degK in the first effect, 13.9 degK in the second effect and 22.2 degK in the third effect. The limiting pressure which must be maintained in the vapor space of the third effect pressure in order for the evaporator to operate is:
a. 60.2 kPa
b. 58.5 kPa
c. 68.7 kPa
d. 50.7 kPa
e. none of the above

4. Poor performance in large packed towers is due mainly to:
a. channeling
b. inefficient heat transfer
c. cavitation
d. flashing
e. none of the above

5. Tertiary treatment of wastewater includes the following operation except:
a. adsorption
b. ion-exchange
c. disinfection
d. reverse osmosis
e. filtration

6. Dehydroginase is a(n)
a. oxidase
b. reductase
c. lyase
d. ligase
e. transferase

7. For turbulent flow of a fluid in a pipe, all are true except:
a. The average velocity will be nearly the same as at the pipe center.
b. Energy lost due to turbulence and friction varies with K.E.
c. Pipe resistance affects the ƒ.
d. Reynolds number < 2,000
e. Flow of gases and low viscosity liquids is usually turbulent.

8. For the completely corrosion resistant stainless steel the minimum % of Cr in the alloy required is:
a. 1.1%
b. 3.2%
c. 8.3%
d. 11%
e. none of the above

9.
a. ADP
b. ATP
c. NAD
d. UDP
e. CDP
is the hydrogen carrier in metabolic reactions.

10. In case of a straight or concave down operating line and a straight or concave down equilibrium line, the maximum liquid rate is that at which
a. The operating line just touches the equilibrium line at the bottom of the tower.
b. The operating line just touches the equilibrium line on the top of the tower
c. The operating line intersects the equilibrium line at the middle of the tower.
d. The slope of the operating line is smaller that of the equilibrium line.
e. None of these