Practice Exams ChE - 30

1. NaOH is produced by reacting 20% aqueous solution of Na2CO3 and 25% Ca(OH)2CaCO3 is precipitated as the solution of NaOH is produced. The precipitate is made up of 94% CaCO3, 5% H2O and 1% NaOH. The number of grams of NaOH formed per 100g precipitate is
a. 28.9
b. 75.2
c. 98.7
d. 21.2
e. none of these

2. A viscous solution containing particles with density = 1461 kg/m^3 is to be clarified by centrifugation. The solution density = 801 kg/m^3 and viscosity = 100 cp. The centrifuge has a bowl with r2 = 0.0225 m, r1 = 0.00716 m and height, b = 0.1970 m. The critical particle diameter of the largest particles is the air stream of N = 23,000 rev/min and flow rate q = 0.002832 m^3/hr is
a. 0.746 m
b. 0.476 x 10-6
c. 4.076 x 10-5
d. 0.736 x 10-6
e. none of these

3. The fixed cost for a steam line per meter of pipe is 350x +18; P/year and the cost for loss of heat from the pipe per meter is 1.6/x; P/year, where x is the thickness of insulation in meters. The optimum thickness of the insulation is
a. 0.068 m
b. 0.68 m
c. 0.088 m
d. 0.072 m
e. none of these

4. a. Pyschrophile
b. Thermophile
c. Halophile
d. Osmophile
e. Microaerophile

is a heat-loving organism

5. 2320 g of tetra-methanol cyclopentane is detonated in the absence of air in a 1000 L closed bomb. The temperature in the bomb if the pressure rises to 300 kPa is
a. 425 K
b. 365 K
c. 285 K
d. 345 K
e. none of these

6. The temperature of a certain material is 0ºC. If the temperature of another material is 1/3 hotter than the first, its temperature is
a. 0ºC
b. 91ºC
c. 182ºC
d. 33.3ºC
e. none of these

7. A contract is made between a buyer and a paper manufacturer for paper containing 5% moisture at P450/tonne FOB on specifications that price adjustment will be made if the quality is different. How much should the buyer pay for 1 tonne of paper with 8% moisture content? Freight cost is P45/tonne.
a. 458
b. 434.16
c. 405
d. 424.26
e. none of these

8. An axial flow propeller pump with a total developed head of 20 feet will have a capacity, in gal/min of:
a. 7000
b. 8500
c. 4000
d. 2000
e. none of these

9. A membrane required** process where the component from a liquid phase, which is heated, permeates through the membrane and is removed under low pressure
a. reverse osmosis
b. dialysis
c. pervaporation
d. micro-filtrate
e. none of these

10. Which is the indicator of sewage pollution?
a. coliform
b. salmonella typhora
c. streptococci
d. staphylococcus aureus
e. bacilli