Chemical Engineering Review Questions

65) A 40,000 lb rocket is launched from sea level straight up, then falls back to earth. The total flight time was 160 seconds. The rocket reached its apex in 1 minute and 20 seconds. What altitude did the rocket reach before falling back to earth?
A) More than 25 miles.
B) Between 15 and 25 miles.
C) Less than 5 miles.
D) None of the above.

16) The pressure of a sample of gas at a constant temperature of 25 degrees C is increased from 1.0 atm to 1.2 atm. If the original volume was 3.8 liters, what will the new volume be?
A) 3.8 liters.
B) 4.56 liters.
C) 3.2 liters.
D) None of the above.

42) The assembly operation takes two minutes for an operator to perform in a manufacturing firm, producing 24,000 such assemblies per year. The hourly cost for the assembler is $10.00 per hour. You, as a new engineer have redesigned the assembly fixture so that it allows the operation to be performed in 20 seconds. Furthermore, it is now possible to use less skilled operators costing $7.50 per hour. The new fixture will cost $20,000 to construct. If the new fixture design is approved, how long will it take for the cost of the fixture to be returned in labor savings? Assume the factory will continue to produce 24,000 assemblies per year.
A) Less than 1 year.
B) Less than 2 years.
C) Less than 3 years.
D) None of the above.

18) A circular cross sectional bar with a diameter of 3.25 inches is loaded with a uniform axial compressive load of 22,750 pounds. What is the compressive stress along a cross section of the bar?
A) Cannot be determined because the length of the bar is unknown.
B) Over 10,000 psi.
C) Less than 1,000 psi.
D) Between 2,000 and 9,000 psi.

21) As the Quality Control Manager of a chemical company, you are asked to decide between several process methods that are supposed to uniformly mix 37.4 milligrams into a chemical solution. The resulting solutions from each process are sampled tested for uniformity. The test samples yielded the following results of percentage powder mixed in the solution:

Method A: 0.13%, 0.21%; 0.009%, 0.014%
Method B: 0.10%; 0.006%; 0.015%; 0.11%; 0.16%
Method C: 0.006%; 0.09%; 0.07%
Method D: 0.18%; 0.16%; 0.19%; 0.17%

Which method would be the best choice to provide a uniform mixture? (Hint: the best selection would be that resulting in the lowest standard deviation of measurements.)
A) Method A.
B) Method B.
C) Method C.
D) Method D.

09) A cylindrical steel beam is 2 inches diameter and 6 feet long. The modulus of elasticity is 30 X 1,000,000 psi. If the beam is subjected to a tensile force of 1000 lbs, what will be the resulting unit strain?
A) 16,000 psi
B) .002 ft-lbs/sq-in
C) 0.000064 ft/ft
D) .0000106 in/in