Compre Exercses Stoic1_2

ChE CALCULATIONS I 1. The equivalent of 45oTw in the Baume scale is A. 28.32 B. 32.48 C. 26.63 D. 42.56 2. How many kilograms of whiting (CaCO3) of specific gravity of 2.2 must be added to 100 kg of water to give a suspension with a specific gravity of 1.15? A. 31.43 B. 32.45 C. 42.38 D. 27.5 o 3. A 10 N aqueous solution of sulfuric acid (30 Tw) is made to react with a 55% aqueous solution of sodium hydroxide (64oBe) to form 1350 g of sodium sulfate per litre of sodium hydroxide solution. The volume ratio of the acid to the base solution is 2:1. The limiting reactant in the reaction is A. NaOH B. H2SO4 C. Na2SO4 D. H2O 4. The degree of completion of the above reaction is A. 85% B. 92% C. 95% D. 72% 5. Battery acid has a density of 1.285 g/mL and contains 38.0% by weight H2SO4. How many grams of pure H2SO4 are contained in a liter of battery acid? A. 430 B. 442 C. 475 D. 488 6. The weight of a sulfuric acid that would be required to prepare 1 liter of hydrochloric acid solution (containing 40.09 percent by weight HCl), density 1.201 is A. 595.3 g B. 646.8 g C. 673.2 g D. 692.4 g 7. One hundred mole per hour of a 40% m solution of ethylene dichloride in toluene is fed into the middle of a distillation column. There is no net accumulation in the column; 100 mole/hr of total material leaves in two streams, an overhead or „distillate‟ stream and a „bottoms‟ stream. The distillate stream contains 95% m ethylene dichloride and the bottoms stream contains 10% m ethylene dichloride. What is the rate of flow of the distillate stream? A. 64.7 mole/hr B. 53.8 mole/hr C. 35.3 mole/hr D. 45.9 mole/hr 8. An experimental oil is used to distill 6000 kg/hr of Athabasta tar sand which analyses 30% „heavy oil‟, „light oil‟, and non-volatile matter. If the distillate contains 12% heavy oil and this constitutes 25% recovery of the component, the weight in kilograms of the distillate obtained is A. 3750 B. 2250 C. 4350 D. 6000 9. The waste acid from a nitration plant operations contains 23% w HNO2, 57% H2SO4, and 20% H2O. It is specified that the concentrated acid product should contain 27% HNO2, 60% H2SO4, and 13% H2O. If the H2SO4 available contains 7% H2O and HNO2, how many pounds of the waste acid is needed to produce 1000lb of the product? A. 193 lb B. 388.7 lb C. 814.3 lb D. 418. 3 lb 10. 90% of the NH3 entering an NH3-oxidation unit is converted to HNO3 and 10% less NH3 is due to conversion losses, NO in the stock gases and miscellaneous losses. The kg of NH3 necessary to produce 60,000 kg 0f 62 wf % HNO3 is A. 11,150 B. 12,000 C. 12,150 D. 11,000 11. Wood is to be dried from 40% to 25% moisture. What % of feed wood is the water evaporated? A. 80 B. 70 C. 25 D. 60 12. One drier will dry a material from 45% moisture(wb) to 20% moisture (d.b.) 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 A. 5% B. 2% C. 3% D. 1% 13. A salt solution originally 4% w NaCl in water is evaporated until the concentration is 5w NaCl. What percentage of the water in the original solution is evaporated? A. 20.8% B. 25% C. 30% D. 35% 14. A contract was made between a buyer and a paper manufacturer for paper containing 5% moisture at P450 per ton on specification that price adjustment will be made if quality is different. How much should the buyer pay for 1 ton of paper with 8% moisture content? Freight cost is P45 per ton. A. P450 B. P434.16 C. P405 D. 424.26 15. A solution containing equimolal O2 and N2 is passed through a membrane to separate O2 from N2. The final product is found to contain 45% O2 and 55% N2. Find the percentage O2 remaining if only 25% of the original solution passed through the membrane. A. 51% B. 15% C. 50% D. 45% o o 16. The solubility of NaNO3 at 40 Cand the 10 C are 51.4% by weight and 44.5% by weight respectively. How many grams of NaNO3 may be crystallized from a 10 kg solution initially saturated at 40oC if the temperature of the solution is lowered to 10oC? A. 6900 B. 4089 C. 3897 D. 1243 ChE 556 ChE COMPRE/Exercises1&2/2nd Sem1415 Prepared by: Engr. Rejie C. Magnaye

17. A dehumidifier sprays 50 lb of cold water per minute into a stream of air. One hundred pounds of wet air per minute enters at the dehumidifying chamber. The absolute humidity of the entering air is 0.05 water/lb dry air, and that of the leaving air is 0.01lb water/lb dry air. What is the weight of wet air leaving per minute? A. 3.81 B. 50 C. 53.81 D. 96.2 o 18. Humid air at temperature 600 F and a total pressure of 1 atmosphere is passed through a dehumidifier at a rate of 1000 ft 3/min. the partial pressure of water vapour in air is reduced from 45 mmHg to 10 mmHg. How many pounds of water is removed from air? A. 81.9 B. 65.4 C. 45.4 D. 76.3 19. A mixing tank mixes two inlet streams containing salt. The salt concentration in stream 1 is 5% by weight, and in stream 2 it is 15% by weight. Stream 1 flows at 25 kg/s and stream 2 at 10 kg/s. There is only one exit stream. Find the salt concentration in the exit stream. A. 5% B. 8% C. 11% D. 13% 20. The chloride concentration in a brine waste flow of 6.3 L/s is 15000mg/L. The river flow upstream from the point of discharge is 0.57m3/s, and the chloride content is 10 mg/L. Calculate the concentration (in mg/L) in the stream below the mixing zone. A. 172 B. 174 C. 176 D. 178 21. Fresh orange juice contains 12.0 wt% solids. Initially a single evaporation process was used for the concentration to 45%, but volatile constituents of the juice escaped with the water, leaving the concentration with a flat taste. The present process overcomes this problem by bypassing the evaporator with a fraction of the fresh juice; the juice that enters the evaporator is concentrated to 58% solids and the product is mixed with the bypassed fresh juice to achieve the desired final concentration of solids. Calculate the fraction of the feed that bypassed the evaporator. A. 5% bypass B. 10% bypass C. 15% bypass D. 30% bypass 22. A typical mud is 70 wt % sand and 30 wt % water. What is its density? The sand is practically pure quartz (SiO2), for which density is 165 lb/ft3. A. 110.4 kg/m3 B. 110.4 lb/ft3 C. 1769 lb/ft3 D. 17.69 kg/L 23. An equimolar mixture of benzene and toluene is subjected to a single batch distillation. Distillation is discontinued when 60% of the benzene in the feed is distilled. At this instance the bottom product when analysed show benzene to be 36.4% by mole. In the distillate the mole % of benzene is A. 66.6 B. 58.1 C. 33.6 D. 54.7 24. How many pounds of calcium fluoride rock is needed to produce 3000lbs of a 60% HF acid per day if the yield is 90% and the rock contains 95% pure CaF2? A. 4105.2 B. 3694.7 C. 3510.0 D. 3900.0 25. A laundry can purchase soap containing 30% of water at a price of $7 per 100 lb f.o.b the factory. The same manufacturer offers soap containing 5% of water. If the freight rate is 60 cents per 100 lb, what is the maximum price that the laundry should pay the manufacturer for the soap containing 5% water? A. $9.71 B. $8.90 C. 7.45 D. $10.45 26. A solution in an evaporator contains 20% by weight of soluble solids, A, the rest being water. After 120 kgs of water are evaporated, it was found that the solution contained 28% A. Calculate the weight of solution originally in the evaporator. A. 420 lbs B. 420 kgs C. 240 lbs D. 240 kgs 27. A 100-kg batch of clay contains 20% water. It was dried to a water content of 5%. How much water is removed? A. 15.8 lbs B. 27.2 lbs C. 15.8 kgs D. 27.2 kgs 28. A salt solution originally 4%w NaCl in water is evaporated until the concentration is 5%w NaCl. What is the percentage reduction in weight of the original solution? A. 20% B. 20.8% C. 21.2% D. 21.4% 29. A mill produces wet paper containing 15% water by weight (wet basis). This wet paper is fed in a continuous steady-state operation through a drier where the water content is reduced to 6% by weight. If the heating cost 5 centavos for every pound of water removed from the paper in the drying operation, what is the heating cost per 100 lb of wet paper fed into the dryer? A. P 1. 50 B. P 0.36 C. P 0.48 D. P 2.00 30. A company receives a shipment of 50000lb is of two chemicals A and B. The total cost, excluding shipping charges, is $15,000. The price of A is 50 cents/lb; the price of B is 25 cents/lb. How many pounds of A were shipped? A. 40000 B. 10000 C. 20000 D. 30000 31. Paper is passing continuously through a tunnel drier. The entering paper contains 10%w H 2O (dry basis) and the leaving paper contains 2%w H2O (dry basis). How many pounds of water is evaporated per hour if 1000 lb/hr of paper enters the drier? A. 90.0 B. 18.18 C. 72.72 D. 25.05 32. One metric ton per hour of palay is to be dried in a tunnel drier from 180% moisture to 10% moisture dry basis. How much water must be removed? ChE 556 ChE COMPRE/Exercises1&2/2nd Sem1415 Prepared by: Engr. Rejie C. Magnaye

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A. 3400 lb/hr B. 110000 lb/hr C. 34000 lb/hr D. 1214 lb/hr The fermentation of glucose produces ethyl alcohol and carbon dioxide. C6H12O6 (aq) 2C2H5OH (aq) + 2CO2 (g). How many grams of ethanol can be produced from 10 g of glucose? A. 10.0 g B. 2.56 g C. 5.11 g D. 4.89 g Automotive airbags inflate when sodium azide, NaN3, rapidly decomposes to its component elements via the reaction 2NaN3 2Na + 2N2. How many grams of sodium azide are required to form 5.00 g of nitrogen gas? A. 9.11 g B. 8.81 g C. 7.74 g D. 3.33 g A starting stock solution has a specific gravity of 1.075 and contains 12.7 wt% sugar. All the sugar is assumed to be C12H22O11. The sugar to water ratio (kg sugar/kgH2O) is ____: A. 1 B. 1.5 C. 0.15 D. 15 A gas mixture consists of three components: argon, B and C. The following analysis of the mixture is given: 40% mol argon, 18.75% mass B and 20% mol % C. The MW of argon is 40 and the molecular weight of C is 50. What is the molecular weight of B? A. 25 B. 63 C. 15 D. 29 An evaporator is concentrating solutions coming from two different sources. The solution from the first source containing 10% NaCl and 10% NaOH flows at the rate of 50 kg per minute. The other solution containing 8% NaCl and 12% NaOH flows at the rate of 70 kg per min. two streams are fed directly to the evaporator. If 50% of the total water is to be evaporated, what is the flow rate in kg/min of the product? A. 50 B. 72 C. 100 D. 48 One thousand kilograms per hour of a mixture containing equal parts by mass of benzene and toluene are distilled. The flow rate of the overhead product stream is 488 kg/hr, and the bottom stream contains 7.11 wt % benzene. Calculate the molar flow rate in (kgmole/hr) of toluene in the overhead product stream A. 0.26 B. 2.96 C. 3.12 D. 9.87 A dryer takes in wet timber (20.1% water) and reduces the water content to 8.6% water. Determine the kg water removed per kg timber that enters. A. 0.245 B. 0.367 C. 0.126 D. 0.568

ChE CALCULATIONS II 1. An oil fired boiler uses a high grade hydrocarbon fuel and reacted with combustion air. The Orsat analysis of the flue gas shows readings of 12.6% CO2, 3.6% O2 and 83.8% N2. Determine the % excess air. A. 16.6 B. 3.5 C. 25.8 D. 19.3 2. A fuel containing 75% ethane and 25% propane is burned with dry air. All the H2 burns to H2O and the CO2 to CO ratio is 10:1. Fifteen percent excess air is supplied. Calculate the % O2 in the stack gas D. 1.04 A. 0.089 B. 2.5 C. 2.98 3. Natural gas containing 80% CH4, 15% C2H6 and 5% C3H8 is burnt with 50% excess air. Assuming that 90% of the carbon in the hydrocarbons is converted to CO2 and the rest to CO. Determine the Orsat Analysis in terms of by mole. A. 7.07% CO, 0.79 CO2, 7.28 O2, 84.86%N2 B. 7.09% CO2, 0.79 CO, 7.68 O2, 82.48%N2 C. 7.07% CO2, 0.79 CO, 7.86 O2, 84.28%N2 D. 7.86% CO, 0.28 CO2, 7.07 O2, 84.09%N2 4. A certain stoichiometric problem was solved on the basis of 100 mole dry fuel gas (DFG). The given conditions at the stack outlet are as follows: 780 mmHg, 970 K, and the partial pressure of H2O is 24 mmHg. The computed total moles of H2O is A. 2.340 B. 4.232 C. 3.175 D. 6.225 5. A certain stoichiometric problem was solved on the basis of 100 mole dry fuel gas (DFG). The given conditions at the stack outlet are as follows: 780 mmHg, 970 K, and the partial pressure of H2O is 24 mmHg. The partial pressure of H2O is equal to ____ in Hg. A. 0.88 B. 0.80 C. 0.85 D. 0.94 6. A certain stoichiometric problem was solved on the basis of 100 mole dry fuel gas (DFG). The given conditions at the stack outlet are as follows: 780 mmHg, 970 K, and the partial pressure of H2O is 24 mmHg. The volume of the wet fuel gas is A. 6.098 m3 B. 8.001 m3 C. 8719 L D. 592 L 7. A certain stoichiometric problem was solved on the basis of 100 mole dry fuel gas (DFG). The given conditions at the stack outlet are as follows: 780 mmHg, 970 K, and the partial pressure of H2O is 24 mmHg. Pressure of the gas stream in psia is: A. 15.09 B. 14.7 C. 22.34 D. 21.71 8. A certain stoichiometric problem was solved on the basis of 100 mole dry fuel gas (DFG). The given conditions at the stack outlet are as follows: 780 mmHg, 970 K, and the partial pressure of H2O is 24 mmHg. Actual volume occupied by the computed moles of H2O is A. 246.22 L B. 256.33 L C. 24.9 L D. 25.6 L ChE 556 ChE COMPRE/Exercises1&2/2nd Sem1415 Prepared by: Engr. Rejie C. Magnaye

9. A certain stoichiometric problem was solved on the basis of 100 mole dry fuel gas (DFG). The given conditions at the stack outlet are as follows: 780 mmHg, 970 K, and the partial pressure of H2O is 24 mmHg. Fuel gas temperature in o F is A. 613 B. 1472 C. 323 D. 1287 10. A pure saturated hydrocarbon is burned with excess air. Orsat analysis of the product of combustion shows 9.08% CO2, 1.63% CO, 5.28% O2 and no free H2. The formula of the hydrocarbon is A. C3H8 B. C4H10 C. C2H6 D. C2H2 11. The hydrocarbon CnH2n+2, used as a fuel was found to contain 14.84 g-moles H2 and 133.56 grams C. What is the formula of the hydrocarbon? A. CH4 B. C2H6 C. C3H8 D. C4H10 12. Coal fired in a furnace has a heating value of 13800 Btu/lb and contains 78.05%C and 1.2%S. The proximate analysis shows 4%M, 24%FC, 8%A and the analysis of the refuse shows 8%VCM, 25%FC and 32% ash. Calculate the % of C lost in the refuse. A. 4.22 B. 8 C. 9.5 D. 17 13. Ninety grams of ethane and 384 grams of oxygen are fed continuously to a laboratory furnace. The total combustion products collected was 16.2 gmole with no carbon dioxide. However, not all of the ethane was burned due to faulty combustion. The fraction of ethane that was burned is equal to A. 0.8 B. 0.5 C. 0.9 D. 0.6 14. The furnace at the Bataan refinery is using a fuel gas which contains methane, ethane and 20% nitrogen. The orsat analysis of the combustion products showed 7.8% CO2, 7.4% O2, and 84.8% N2. The gas is burned with excess air. The % methane in the fuel gas is A. 63.25 B. 57.24 C. 51.2 D. 22.76 15. A furnace is fired with coal with the following proximate analysis: 5% M, 60% FC, 25% VCM and 10% ash. Its calorific value is 31.33 MJ/kg. Calculate the % VCM lost in the refuse if the refuse analyses 25% FC, 4.4% VCM, 70.6% ash. A. 5.1 B. 4.59 C. 2.21 D. 3.54 16. A sample of lignite was found to contain 34.55% moisture, 22.91% FC, 7.2% ash, 1.1% S and 0.57% N with a calorific value of 16.45 MJ/kg. Calculate % C in the coal. A. 46.15% B. 49.09% C. 65.76% D. 55.40% 17. On the “dry basis” a sample of coal analyses as follows: VCM, 21.06%; FC, 71.80% and ash, 7.14%. If the moisture present in the coal is 2.49%, what is the % FC on the wet basis? A. 70.0% B. 70.8% C. 71.5% D. 71.8% 18. The fuel gas from the combustion of a hydrocarbon fuel has the following Orsat analysis: 5.68% CO 2, 2.43% CO, 6.4% O2, and 85.4% N2. The percent excess air supplied is: A. 30.0% B. 34.8% C. 38.6% D. 42.5% 19. A furnace burns coal containing 4.1% moisture, 24% VCM, 63% FC, 1.2% N, 1.8% S, and 8.9% ash. The coal has a heating of 32,000 kJ/kg and the refuse was analysed to contain 4.8% VCM, 12.6% FC and 82.6% ash. The type of combustible present is A. coked coal C. uncoked coal B. coked and uncoked coal D. partially coked coal 20. A furnace burns coal containing 4.1% moisture, 24% VCM, 63% FC, 1.2% N, 1.8% S, and 8.9% ash. The coal has a heating of 32,000 kJ/kg and the refuse was analysed to contain 4.8% VCM, 12.6% FC and 82.6% ash. The percentage of the carbon lost in the refuse is A. 2.16% B. 2.97% C. 3.02% D. 2.98% 21. Orsat analysis of the stack gas from the combustion of the gaseous mixture of ethane and methane shows 10.57% CO 2, 3.79% O2, and the rest N2. The air enters at 30oC and the barometer reads 760 mmHg. Determine percent excess air A. 50 B. 20 C. 45 D. 65 22. Orsat analysis of the stack gas from the combustion of the gaseous mixture of ethane and methane shows 10.57% CO 2, 3.79% O2, and the rest N2. The air enters at 30oC and the barometer reads 760 mmHg. Determine mole percent composition of the gaseous fuel A. 85.3% methane and 14.7% ethane C. 30.61% methane and 69.39% ethane B. 79.3% methane and 20.7% ethane D. 14.7% methane and 85.3% ethane 23. Orsat analysis of the stack gas from the combustion of the gaseous mixture of ethane and methane shows 10.57% CO 2, 3.79% O2, and the rest N2. The air enters at 30oC and the barometer reads 760 mmHg. Determine if the partial pressure of water in the stack gas is 127 mmHg, what is the relative humidity of the incoming air? A. 88% B. 80% C. 70% D. 66% 24. What will be the percent carbon monoxide in the flue gas from the burning of carbon with 50% excess air in such a manner that 80% carbon burns to carbon dioxide and the rest to carbon monoxide? A. 2.8 B. 17.2 C. 8.3 D. 20.5 25. A furnace is fired with petroleum oil containing 80% C, 13% H, 3% S, 1% N, and 3% O. Determine the moles of theoretical air required for the combustion of one kilogram of oil. ChE 556 ChE COMPRE/Exercises1&2/2nd Sem1415 Prepared by: Engr. Rejie C. Magnaye

A. 430 B. 460 C. 472 D. 491 26. A Pennyslavania bituminous coal is analysed as follows: Exactly 2.500 g is weighed into a fused crucible. After drying for 1 h at 1110OC, the moisture-free residue weighs 2.145 g. the crucible next is covered with a vented lid a strongly heated until no volatile matter remains. The residual coke button weighs 1.528 g. The crucible is then heated without the cover until all specks of carbon have disappeared, and the final ash weighs 0.245 g. What is the percent of VCM in the coal? A. 35.5% B. 3.4% C. 51.3% D. 9.8% 27. The CO2 that will theoretically be formed when a mixture of 50 g of CH4 and 100 g of O2 is ignited? A. 34.4 g B. 68.8 g C. 103.1 g D. 137.5 g 28. Determine the theoretical moles of air required for the combustion of one mole of refinery gases containing 6% H2S, 5% H2, 57% C3H8, 2% CO2, and 30% C4H10. A. 3.450 B. 4.010 C. 4.786 D. 4.915 28. The data from a certain flue gas analysis are as follows: Original volume of sample - 100 mL Volume after passing through KOH solution (removes CO2) - 87.9 mL Volume after passing through alkaline pyrogallol solution (removes O2) - 80.7 mL Volume after passing through cuprous chloride solution (removes CO) - 80.5 mL On dry basis, what is the percentage of oxygen in the flue gas sample? A. 12.1 B. 4.7 C. 0.2 D. 7.2 29. Ethane reacts with pure oxygen to form water and carbon dioxide. If 3 moles of ethane and 12 moles of oxygen is mixed and 80% of the ethane reacts, what is the percent excess of oxygen? A. 14.3% B. 20.5% C. 30.2% D. 50% 30. Ninety grams of ethane and 384 grams of oxygen are fed continuously to a laboratory furnace. The total combustion products collected was 16.2 g-mole with no carbon monoxide. However, not all of the ethane was burned due to faulty combustion. The fraction of ethane that was burned is equal to A. 90% B. 85% C. 80% D. 92% 31. A fuel gas containing 80%m CH4 and 20%m C2H6 is burned with dry air. Sixty percent of the carbon burned goes to CO2; the rest going to CO. Fifty percent excess air is used. Calculate the mole percent of CO in the Orsat analysis of the fuel gas. A. 4.62% B. 3.08% C. 8.91% D. 83.39% 32. A high speed diesel engine burns fuel to give an exhaust gas analysing 7.14% CO 2, 4.28% CO, 8.24% O2 and 8.34% N2. Calculate the percent excess supplied. A. 28 B. 30 C. 32 D. 34 33. The exhaust gases from a furnace give the following Orsat analysis: 13.6% CO 2, 2.4% CO, 2.8 O2, and 81.2% N2. If the fuel used is hydrocarbon, identify the fuel. A. C2H6 B. CH2 C. C2H2 D. C2H4 34. Pure carbon is burned with theoretical amount of air for complete combustion in lb moles, 80% carbon burns, one-half of which formed CO2 and the rest CO. The percentage of CO2, CO, and O2 in the combustion gases are respectively: A. 33.3, 33.3, 33.3 B. 8.1, 8.1, 8.1 C. 4.8, 8.1, 12.2 D. 81, 4.0, 12.0 35. A furnace completely burns coal containing 80% C. Analysis of the fuel gas shows 14.5% CO 2, 3.76% O2, and no CO. What is the percentage of the net hydrogen in the coal? A. 6.37% B. 8.90% C. 10.12% D. 14.25% 36. A sample of lignite was found to contain 34.55% moisture, 22.91% FC, 7.2% ash, 1.1% S, and 0.57% N with a calorific value of 16.45 MJ/kg. Calculate % C in the VCM. A. 49.09% B. 46.15% C. 65.76% D. 55.40% 37. A furnace is fired with coal with the following proximate analysis: 5% M, 60% FC, 25% VCM and 10% ash. Its calorific value is 31.33 MJ/kg. Calculate the % C lost in the refuse if the refuse analyses 25% FC, 4% VCM, 79.6% ash. A. 4.59 B. 5.1 C. 2.25 D. 3.54 38. A furnace burns coal containing 4.1% M, 24% VCM, 63% FC, 1.2% N, 1.18% S, and 8.9% ash. Determine the percentage of the heating value lost in the refuse if it analyses 24% FC and 76% ash. Its calorific value is 32MJ/kg. A. 2.42% B. 2.97% C. 3.54% D. 4.23% 39. A fumace is fired with coal containing 6% moisture,18% VCM, 67% FC and 9% ash. The refuse analysis shows 5% VCM, 23% FC and 62% ash. The higher heating value of the coal as fired is 14,300 Btu/lb. Calculate the percentage of the heating value of the coal that is lost in the refuse. Assume that the moisture in the refuse is due to the „wetting down‟ to prevent dusting and not moisture from the original coal. A. 4.68% B. 7.02% C. 9.36% D. 15.0%

ChE 556 ChE COMPRE/Exercises1&2/2nd Sem1415 Prepared by: Engr. Rejie C. Magnaye