CHECAL PT.1

Question 1

Wine making involves a series of very complex reactions most of which are performed by microorganisms. The starting concentration of sugars determines the final alcohol content and sweetness of the wine. The specific gravity of the starting stock is therefore adjusted to achieve desired quality of wine. A starting stock solution has a specific gravity of 1.075 and contains 12.7 wt% sugar. If all the sugar is assumed to be C12H22O11, determine kg sugar / kg H2O

Answer 1

0.145

Question 2

Wine making involves a series of very complex reactions most of which are performed by microorganisms. The starting concentration of sugars determines the final alcohol content and sweetness of the wine. The specific gravity of the starting stock is therefore adjusted to achieve desired quality of wine. A starting stock solution has a specific gravity of 1.075 and contains 12.7 wt% sugar. If all the sugar is assumed to be C12H22O11, determine lb solution / ft^3 solution

Answer 2

67.1

Question 3

Wine making involves a series of very complex reactions most of which are performed by microorganisms. The starting concentration of sugars determines the final alcohol content and sweetness of the wine. The specific gravity of the starting stock is therefore adjusted to achieve desired quality of wine. A starting stock solution has a specific gravity of 1.075 and contains 12.7 wt% sugar. If all the sugar is assumed to be C12H22O11, determine g sugar / L solution

Answer 3

136

Question 4

Two aqueous sulfuric acid solutions containing 20 wt% H2SO4 (SG=1.139) and 60 wt% H2SO4 (SG=1.498) are mixed to form a 4 M solution (SG=1.213). Calculate the mass fraction of sulfuric acid in the product solution.

Answer 4

0.323

Question 5

Two aqueous sulfuric acid solutions containing 20 wt% H2SO4 (SG=1.139) and 60 wt% H2SO4 (SG=1.498) are mixed to form a 4 M solution (SG=1.213). Calculate the feed ratio (liters 20% solution per liter 60% solution)

Answer 5

2.96

Question 6

Two aqueous sulfuric acid solutions containing 20 wt% H2SO4 (SG=1.139) and 60 wt% H2SO4 (SG=1.498) are mixed to form a 4 M solution (SG=1.213). What feed rate of the 60% solution (L/hr) would be required to produce 1250 kg/h of the product.

Answer 6

257 L/h

Question 7

If 1 L of ethyl alcohol is mixed with 1 L of water at 200C. How many kilograms of solution result?

Answer 7

1.79

Question 8

If 1 L of ethyl alcohol is mixed with 1 L of water at 200C. How many liters?

Answer 8

1.93

Question 9

Air is bubbled through a drum of liquid hexane at a rate of 0.10 kmol/min. The gas stream leaving the drum contains 10 mol% hexane vapor. Air may be considered insoluble in liquid hexane. Use an integral balance to estimate the time required to vaporize 10 m3 of the liquid.

Answer 9

6900

Question 10

Urea, phosphoric acid and potassium chloride are mixed together to obtain a mixed fertilizer having NPK content 10:26:26 as %N, %P2O5 and %K2O by weight, balance being the weight of filler materials. Calculate the amount of potassium chloride to be mixed to get 1000 kg of mixed fertilizer.

Answer 10

411.5 kg

Question 11

A supplier shipped a material for chicken feed with the following analytical report: protein – 22%, triglyceride – 8%, moisture – 10%. During transport moisture was picked up by the material; the later analytical report showed 14% moisture. Based on the latest report, recalculate the % triglyceride.

Answer 11

7.64%

Question 12

An evaporator is fed continuously with 25 MT/h of a solution consisting of 10% NaOH, 10% NaCl, and 80% H2O. During
evaporation, water is boiled off, and salt precipitates as crystals, which are settled and removed from the remaining liquor. The concentrated liquor leaving the evaporator contains 50% NaOH, 2% NaCl and 48% H2O. Calculate the kg of water evaporated per hour

Answer 12

17600

Question 13

An evaporator is fed continuously with 25 MT/h of a solution consisting of 10% NaOH, 10% NaCl, and 80% H2O. During
evaporation, water is boiled off, and salt precipitates as crystals, which are settled and removed from the remaining liquor. The concentrated liquor leaving the evaporator contains 50% NaOH, 2% NaCl and 48% H2O. Calculate the kg salt precipitated per hour

Answer 13

2400

Question 14

An evaporator is fed continuously with 25 MT/h of a solution consisting of 10% NaOH, 10% NaCl, and 80% H2O. During
evaporation, water is boiled off, and salt precipitates as crystals, which are settled and removed from the remaining liquor. The concentrated liquor leaving the evaporator contains 50% NaOH, 2% NaCl and 48% H2O. Calculate the kg of concentrated liquor produced per hour

Answer 14

5000

Question 15

Ten kilograms each of salts A and B are dissolved in 50 kg of
water. The solubility of A in water is 1 kg per kg water and that of B is 0.5 kg per kg of water. The solution is heated to evaporate water. When the concentration of the solution reaches the saturation concentration of any salt, further evaporation results in the crystallization of that salt. If 70% of the water that is originally present in the solution is driven off by evaporation, determine the weight of the final solution.

Answer 15

32.5

Question 16

Ten kilograms each of salts A and B are dissolved in 50 kg of
water. The solubility of A in water is 1 kg per kg water and that of B is 0.5 kg per kg of water. The solution is heated to evaporate water. When the concentration of the solution reaches the saturation concentration of any salt, further evaporation results in the crystallization of that salt. If 70% of the water that is originally present in the solution is driven off by evaporation, determine the weight of the crystals formed.

Answer 16

2.5

Question 17

1200 lb of barium nitrate is dissolved in sufficient water to form a saturated solution at 900C. Assuming that 5% of the weight of the original solution is lost through evaporation calculate the crop of crystals obtained when cooled at 200C. Solubility data for barium nitrate at 900C is 30.6% wt and 8.6 wt% at 200C.

Answer 17

962.4

Question 18

What is the theoretical yield of crystals which may be obtained by cooling a solution containing 1000 kg of sodium sulfate (mw = 142 kg/kmol) in 5000 kg water to 283 K? The solubility of sodium sulfate at 283 K is 9 kg anhydrous salt / 100 kg water and the deposited crystals will consist of decahydrate. It may be assumed that 2% of the water will be lost by evaporation during cooling.

Answer 18

1430.83 kg

Question 19

A solution of NH4Cl is saturated at 700C. Calculate the temperature to which this solution must be cooled in order to crystallize out of 45% of the NH4Cl. The solubility of NH4Cl in water are:
Temperature, C |70|10|0|
Solubility, g/100g H2O |60.2|33.3|29.4|

Answer 19

9.5

Question 20

In the azeotropic distillation of an ethanol–water solution, a feed mixture containing 95.6% alcohol is mixed with pure benzene and distilled. The benzene forms a ternary azeotrope with alcohol– water with a composition of 74.1% benzene, 7.4% water and 18.5% alcohol, which is distilled over as the overhead product. Absolute alcohol is obtained as the residue product. Determine the quantity of benzene required for producing 100 kg of absolute alcohol.

Answer 20

52 kg

Question 21

Oil is extracted from seeds by leaching with organic solvents. Soybean seeds containing 20% oil, 65% inert solids and 15% water are leached with hexane and after extraction the solid residue is removed from the solution of oil in hexane. The residue analyzed 1.0% oil, 88% inert cake and 11% water. What percent of oil is recovered?

Answer 21

96%

Question 22

Acetone is recovered from an acetone-air mixture containing 25% (volume) acetone by scrubbing with water. Assuming that air is insoluble in water, determine the percent of acetone in the entering gas that is absorbed if the gas leaving the scrubber analyzes 5% acetone.

Answer 22

84%

Question 23

One hundred pounds of solution containing 80 wt% Na2SO4 must be obtained by evaporating a dilute solution using a double effect evaporator. If the evaporator from the 2nd effect is 60% of that coming from the first effect and the concentrate of the first effect contains 1 lb Na2SO4 per pound of water. Calculate for the composition of the feed.

Answer 23

31% Na2SO4

Question 24

One drier will dry a material from 45% moisture (wb) to 20%
moisture (db) from here the material enters another drier where the H2O content is further reduced to give a final product weighing 1000 kg. If the total evaporation from both driers is 800 kg, the moisture of the final product is

Answer 24

1%

Question 25

An aqueous solution containing 15% NaOH and 0.5% NaCl is
concentrated at a rate of 100 kg/min in an evaporator. The
concentrated solution is then mixed with 2000 kg of aqueous NaOH solution in a mixer. At the end of one hour a sample is collected from the mixer and analyzed. The analysis shows 40% NaOH and 0.8574% NaCl. Calculate the concentration of the original solution in the receiver.

Answer 25

25% NaOH

Question 26

An aqueous solution containing 15% NaOH and 0.5% NaCl is
concentrated at a rate of 100 kg/min in an evaporator. The
concentrated solution is then mixed with 2000 kg of aqueous NaOH solution in a mixer. At the end of one hour a sample is collected from the mixer and analyzed. The analysis shows 40% NaOH and 0.8574% NaCl. Calculate the mass of water (in kilograms) evaporated in one hour

Answer 26

4500 kg