Multiple choice question for engineering
Set 1
1. What is the heat of reaction if the heat of combustion of products is 10 J and heat of combustion of reactants is 5 J?
a) -5 J
b) 5 J
c) 10 J
d) Cannot be determined
Answer
Answer: a [Reason:] Heat of reaction = 5 – 10 = -5 J.
2. What is the heat of reaction if the heat of combustion of products is 10 J and heat of combustion of reactants is 15 J?
a) -5 J
b) 5 J
c) 10 J
d) Cannot say
Answer
Answer: b [Reason:] Heat of reaction = 15 – 10 = 5 J.
3. What is the heat of reaction if the heat of combustion of products is 40 J and heat of combustion of reactants is 25 J?
a) 5 J
b) 10 J
c) 15 J
d) -15 J
Answer
Answer: d [Reason:] Heat of reaction = 25 – 40 = -15 J.
4. What is the heat of reaction if the heat of combustion of products is 25 J and heat of combustion of reactants is 15 J?
a) -5 J
b) 5 J
c) -10 J
d) 10 J
Answer
Answer: c [Reason:] Heat of reaction = 15 – 25 = -10 J.
5. What is the heat of reaction if the heat of combustion of products is 2 J and heat of combustion of reactants is 10 J?
a) 8 J
b) -8 J
c) 4 J
d) -4 J
Answer
Answer: a [Reason:] Heat of reaction = 10 – 2 = 8 J.
6. What is the heating value of 10 Kg of coal with heat of combustion 10 J/Kg?
a) -10 J
b) 10 J
c) -100 J
d) 100 J
Answer
Answer: c [Reason:] Heating value = – Heat of combustion = -10*10 = -100 J.
7. What is the heating value of 2 Kg of coal with heat of combustion 15 J/Kg?
a) -15 J
b) 15 J
c) -30 J
d) 30 J
Answer
Answer: c [Reason:] Heating value = – Heat of combustion = -15*2 = -30 J.
8. What is the difference between higher heating value and lower heating value if the product has 5 mole of H2O and Enthalpy of vaporization is 10 J/mole at standard conditions?
a) 10 J
b) -10 J
c) 50 J
d) -50 J
Answer
Answer: c [Reason:] HHV – LHV = 5*10 = 50 J.
9. What is the difference between lower heating value and higher heating value if the product has 2 mole of H2O and Enthalpy of vaporization is 40 J/mole at standard conditions?
a) -40 J
b) 40 J
c) -80 J
d) 80 J
Answer
Answer: c [Reason:] LHV – HHV = -2*40 = -80 J.
10. What is the value of higher heating value if the value of lower heating value is 10 J and the product has 5 mole of H2O and Enthalpy of vaporization is 4 J/mole at standard conditions?
a) 10 J
b) 20 J
c) 30 J
d) 40 J
Answer
Answer: c [Reason:] HHV = 10 + 5*4 = 30 J.
11. What is the heat of reaction for CH4 + 2O2 -> CO2 + 2H2O, if the heat of combustion of H2O = 5 J, CO2 = 10 J, O2 = 0, and CH4 = 25 J?
a) -5 J
b) 5 J
c) -10 J
d) 10 J
Answer
Answer: b [Reason:] Heat of reaction = 25 + 0 – 10 – 2*5 = 5 J.
12. What is the heat of reaction for N2 + 3H2 -> 2NH3, if the heat of combustion of N2 = 5 J, H2 = 2 J, and NH3 = 15 J?
a) -5 J
b) 5 J
c) -19 J
d) 19 J
Answer
Answer: c [Reason:] Heat of reaction = 3*2 + 5 – 15*2 = -19 J.
13. What is the heat of reaction for 2CO + O2 -> 2CO2, if the heat of combustion of CO = 20 J, O2 = 5 J, and CO2 = 25 J?
a) 5 J
b) -5 J
c) 15 J
d) -15 J
Answer
Answer: c [Reason:] Heat of reaction = 20*2 + 5 – 2*25 = -5 J.
14. What is the heat of reaction for H2 + Cl2 -> 2HCl, if the heat of combustion of H2 = 2 J, Cl2 = 10 J, and HCl = 10 J?
a) -8 J
b) 8 J
c) -10 J
d) 10 J
Answer
Answer: a [Reason:] Heat of reaction = 10 + 2 – 2*10 = -8 J.
15. What is the heat of reaction for C6H6 + 3H2 -> C6H12, if the heat of combustion of H2 = 2 J, C6H6= 30 J, and C6H12 = 25 J?
a) -6 J
b) 6 J
c) -11 J
d) 11 J
Answer
Answer: d [Reason:] Heat of reaction = 30 + 2*3 – 25 = 11 J.
Set 2
1. The standard heat of reaction is heat of reaction for how many mole of compound?
a) 0
b) 1
c) 2
d) 3
Answer
Answer: b [Reason:] The standard heat of reaction is heat of reaction for one mole of compound.
2. What is the heat of reaction for CH4 + 2O2 -> CO2 + 2H2O, if heat of formation of CH4, O2, CO2 and H2O are 10 J, 5 J, 6 J, and 12 J respectively?
a) -10 J
b) 10 J
c) -20 J
d) 20 J
Answer
Answer: b [Reason:] Heat of reaction = 2*12 + 6 – 2*5 – 10 = 10 J.
3. What is the heat of reaction for 2H2 + O2 -> 2H2O, if heat of formation of H2, O2, and H2O are 2 J, 5 J, and 10 J respectively?
a) 2 J
b) 5 J
c) 8 J
d) 11 J
Answer
Answer: d [Reason:] Heat of reaction = 2*10 – 2*2 – 5 = 11 J.
4. What is the heat of reaction for C2H4 + 3O2 -> 2CO2 + 2H2O, if heat of formation of C2H4, O2, CO2, and H2O are 10 J, 5 J, 6 J and 2 J respectively?
a) -4 J
b) -2 J
c) 0
d) 4 J
Answer
Answer: a [Reason:] Heat of reaction = 2*2 + 2*6 – 10 – 2*5 = -4 J.
5. What is the heat of reaction for C6H6 + 3H2 -> C6H12, if heat of formation of C6H6, H2, and C6H12 are 25 J, 5 J and 50 J respectively?
a) 10 J
b) 20 J
c) 30 J
d) 35 J
Answer
Answer: a [Reason:] Heat of reaction = 50 – 3*5 – 25 = 10 J.
6. What is the enthalpy of reaction for C + O2 -> CO2, if the conversion of C is 50%, and heat of formation of C, O2, and CO2 are 0, 0 and 10 J.
a) 5 J
b) 10 J
c) 15 J
d) 20 J
Answer
Answer: a [Reason:] Heat of reaction = 10*0.5 – 0 – 0 = 5 J.
7. What is the enthalpy of reaction for CH4 + 2O2 -> CO2 + 2H2O, if the conversion of CH4 is 50%, and heat of formation of CH4, O2, CO2, and H2O are 10 J, 0, 6 J and 4 J?
a) 0
b) 2 J
c) 4 J
d) 6 J
Answer
Answer: b [Reason:] Heat of reaction = 2*4*0.5 + 6*0.5 + 10*0.5 – 2*0 – 10 = 4 + 3 + 5 – 10 = 2 J.
8. What is the enthalpy of reaction for C2H4 + 3O2 -> 2CO2+ 2H2O, if the conversion of CH4 is 50%, and heat of formation of CH4, O2, CO2, and H2O are 10 J, 0, 6 J and 4 J?
a) 0
b) 2 J
c) 5 J
d) 10 J
Answer
Answer: d [Reason:] Heat of reaction = 2*4*0.5 + 2*6*0.5 + 10*0.5 – 0 – 10*0.5 = 10 J.
9. What is the enthalpy of reaction for CO2 + 4H2 -> 2H2O + CH4, if the conversion of CO2 is 50%, and heat of formation of CO2, H2, H2O, and CH4 are 6 J, 0, 4 J and 10 J?
a) 2 J
b) 5 J
c) 6 J
d) 9 J
Answer
Answer: d [Reason:] Heat of reaction = 10*0.5 + 2*4*0.5 + 6*0.5 – 6*0.5 = 9 J.
10. What is the enthalpy of reaction forC6H6 -> 3C2H2, if the conversion of C6H6 is 80%, and heat of formation of C6H6, and C2H2 are 24 J, and 8 J?
a) 0
b) 2.4 J
c) 4.8 J
d) 5.6 J
Answer
Answer: c [Reason:] Heat of reaction = 3*8*0.8 + 24*0.2 – 24*0.8 = 4.8 J.
11. What is the enthalpy change of a reaction at 45oC, if the enthalpy of reactant at 45oC and 25oC are 10 J and 6 J, and enthalpy of product at 45oC and 25oC are 15 J and 8 J, and the enthalpy change of reaction at 25oC is 10 J?
a) 14 J
b) 21 J
c) 27 J
d) 34 J
Answer
Answer: b [Reason:] Heat of reaction = (10 – 6) + (15 – 8) + 10 = 21 J.
12. What is the enthalpy change of a reaction at 35oC, if the enthalpy of reactant at 35oC and 25oC are 18 J and 10 J, and enthalpy of product at 35oC and 25oC are 12 J and 8 J, and the enthalpy change of reaction at 25oC is 15 J?
a) 9 J
b) 14 J
c) 22 J
d) 27 J
Answer
Answer: d [Reason:] Heat of reaction = (18 – 10) + (12 – 8) + 15 = 27 J.
13. What is the enthalpy change of a reaction at 35oC, if the enthalpy of reactant at 35oC and 25oC are 22 J and 15 J, and enthalpy of product at 35oC and 25oC are 10 J and 5 J, and the enthalpy change of reaction at 25oC is 36 J?
a) 12 J
b) 24 J
c) 36 J
d) 48 J
Answer
Answer: d [Reason:] Heat of reaction = (22 – 15) + (10 – 5) + 36 = 7 + 5 + 36 = 48 J.
14. What is the enthalpy change of a reaction at 30oC, if the enthalpy of reactant at 30oC and 25oC are 18 J and 15 J, and enthalpy of product at 30oC and 25oC are 10 J and 8 J, and the enthalpy change of reaction at 25oC is 45 J?
a) 10 J
b) 25 J
c) 50 J
d) 100 J
Answer
Answer: c [Reason:] Heat of reaction = (18 – 15) + (10 – 8) + 45 = 50 J.
15. What is the enthalpy change of a reaction at 90oC, if the enthalpy of reactant at 90oC and 25oC are 60 J and 25 J, and enthalpy of product at 90oC and 25oC are 80 J and 10 J, and the enthalpy change of reaction at 25oC is 5 J?
a) 10 J
b) 50 J
c) 110 J
d) 150 J
Answer
Answer: c [Reason:] Heat of reaction = (60 – 25) + (80 – 10) + 5 = 110 J.
Set 3
1. What is the specific humidity, if mass of water is 10 g and mass of bone dry air is 20 g?
a) 10%
b) 30%
c) 50%
d) 80%
Answer
Answer: c [Reason:] H = 10/20*100 = 50%.
2. What is the specific humidity, if mass of water is 15 g and mass of bone dry air is 25 g?
a) 10%
b) 30%
c) 40%
d) 60%
Answer
Answer: d [Reason:] Specific humidity = 15/25*100 = 60%.
3. What is the specific humidity, if pressure of water is 5 atm and total pressure is 10 atm?
a) 25%
b) 50%
c) 75%
d) 100%
Answer
Answer: d [Reason:] Specific humidity = 5/(10 – 5)*100 = 100%.
4. What is the specific humidity, if pressure of water is 2 atm and total pressure is 12 atm?
a) 20%
b) 40%
c) 50%
d) 80%
Answer
Answer: d [Reason:] Specific humidity = 2/(12 – 2)*100 = 20%.
5. What is the specific humidity, if moles of water are 4 and total moles are 5?
a) 20%
b) 80%
c) 200%
d) 400%
Answer
Answer: d [Reason:] Specific Humidity = 4/(5 – 4)*100 = 400%.
6. What is the humid heat of a mixture of air (CP = 10 J) with water vapor (CP = 20 J), if the humidity is 25%?
a) 10 J
b) 15 J
c) 20 J
d) 25 J
Answer
Answer: b [Reason:] CS = 10 + 20*0.25 = 15 J.
7. What is the humid heat of a mixture of air (CP = 20 J) with water vapor (CP = 30 J), if the humidity is 40%?
a) 24 J
b) 32 J
c) 38 J
d) 44 J
Answer
Answer: b [Reason:] CS = 20 + 30*0.4 = 32 J.
8. What is the humid heat of a mixture of air (CP = 10 J) with water vapor (CP = 15 J), if the humidity is 40%?
a) 16 J
b) 20 J
c) 24 J
d) 32 J
Answer
Answer: a [Reason:] CS = 10 + 15*0.4 = 16 J.
9. What is the humid heat of a mixture of air (CP = 10 J) with water vapor (CP = 15 J), if the humidity is 60%?
a) 10 J
b) 14 J
c) 19 J
d) 23 J
Answer
Answer: c [Reason:] CS = 10 + 15*0.6 = 19 J.
10. What is the humid heat of a mixture of air (CP = 10 J) with water vapor (CP = 25 J), if the humidity is 20%?
a) 15 J
b) 20 J
c) 25 J
d) 30 J
Answer
Answer: a [Reason:] CS = 10 + 25*0.2 = 15 J.
11. Which of the following is the summation of volume of 1 Kg of dry air and the water vapor in the air?
a) Humid volume
b) Partial volume
c) Dry volume
d) None of the mentioned
Answer
Answer: a [Reason:] Humid volume is the summation of volume of 1 Kg of dry air and the water vapor in the air.
12. What is the humid volume of the system at 100oF with humidity 20%?
a) 18.6 ft3/lb
b) 22.4 ft3/lb
c) 26.5 ft3/lb
d) 29.4 ft3/lb
Answer
Answer: a [Reason:] V = (0.73T + 336)(1/29 + H/18) = (0.73*100 + 336)(1/29 + 0.2/18) = 18.6 ft3/lb.
13. What is the humid volume of the system at 200oF with humidity 40%?
a) 14.2 ft3/lb
b) 23.4 ft3/lb
c) 29.5 ft3/lb
d) 31.6 ft3/lb
Answer
Answer: d [Reason:] V = (0.73*200 + 336)(1/29 + 0.4/18) = 31.6 ft3/lb.
14. What is the humid volume of the system at 150oF with humidity 50%?
a) 12.4 ft3/lb
b) 19.5 ft3/lb
c) 27.7 ft3/lb
d) 36.1 ft3/lb
Answer
Answer: c [Reason:] V = (0.73*150 + 336)(1/29 + 0.5/18) = 27.7 ft3/lb.
15. What is the humid volume of the system at 300oF with humidity 30%?
a) 15.5 ft3/lb
b) 28.4 ft3/lb
c) 39.8 ft3/lb
d) 55.2 ft3/lb
Answer
Answer: b [Reason:] V = (0.73*300 + 336)(1/29 + 0.3/18) = 28.4 ft3/lb.
Set 4
1. Which of the following term does not involve in ideal gas law?
a) Pressure
b) Volume
c) Temperature
d) Time
Answer
Answer: d [Reason:] Ideal gas law is PV = nRT, which does not involve time.
2. What is the shape of a P-T curve for ideal gas?
a) Straight line
b) Parabolic
c) Hyperbolic
d) Ellipse
Answer
Answer: a [Reason:] P-T curve is straight line for ideal gas.
3. What is the shape of a V-T curve for ideal gas?
a) Straight line
b) Parabolic
c) Hyperbolic
d) Ellipse
Answer
Answer: a [Reason:] V-T curve is straight line for ideal gas.
4. What is the shape of a P-V curve for ideal gas?
a) Straight line
b) Parabolic
c) Hyperbolic
d) Ellipse
Answer
Answer: c [Reason:] P-V curve is hyperbolic for ideal gas.
5. Which of the following is not true about ideal gas molecules?
a) They have negligible size
b) They do not have attractive forces
c) They do not apply pressure
d) They move in random motion
Answer
Answer: c [Reason:] Ideal gas molecules apply pressure to the walls of container.
6. What is the pressure of a 5 liter/mole ideal gas at temperature 27oC?
a) 2.5 atm
b) 3.8 atm
c) 4.4 atm
d) 5.3 atm
Answer
Answer: d [Reason:] PV = nRT, => P*5 = 0.0821*300, => P = 5.3 atm.
7. What is the Temperature of a 2 liter/mole ideal gas with pressure 10 atm?
a) 243.6 K
b) 268.4 K
c) 289.1 K
d) 313.5 K
Answer
Answer: a [Reason:] PV = nRT, => 10*2 = 0.0821*T, => T = 243.6 K.
8. First of the two ideal gases has twice molar volume as much as the second at same temperature, what is the ratio of their pressures?
a) 4:1
b) 1:4
c) 2:1
d) 1:2
Answer
Answer: d [Reason:] P1V1 = n1RT1, P2V2 = n2RT2 dividing both the equations, => P1 2 = 1:2.
9. 88 grams of CO2 at 27oC is applying 5 atm pressure, what is the volume occupied by it?
a) 5.6 liter
b) 7.9 liter
c) 9.8 liter
d) 12.2 liter
Answer
Answer: c [Reason:] n = 88/44 = 2, PV = nRT, => 5*V = 2*0.0821*300, => V = 9.8 liter.
10. What is the density of O2 at 27oC with pressure 1 atm?
a) 1.1 g/L
b) 1.3 g/L
c) 1.5 g/L
d) 1.7 g/L
Answer
Answer: b [Reason:] Molecular wt. of O2= 44 g, PV = nRT, => PV = (m/M)RT, => d = PM/RT = (1*32)/(0.0821*300) = 1.3 g/L.
11. What is the molecular mass of an ideal gas with pressure 1 atm, and density 10 g/L at temperature 27oC?
a) 84.5 g
b) 135.1 g
c) 186.8 g
d) 246.3 g
Answer
Answer: d [Reason:] M = dRT/P = 10*0.0821*300/1 = 246.3 g.
12. What is the specific gravity of CO2 at 27oC and pressure 1 atm with respect to air of with density 1 g/L?
a) 1.23
b) 1.55
c) 1.78
d) 1.96
Answer
Answer: c [Reason:] Density of CO2 = PM/RT = 1*44/(0.0821*300) = 1.78 g/L, => Specific gravity = 1.78/1 = 1.78.
13. What is the specific gravity of CO at 27oC and pressure 5 atm with respect to air (molecular wt. = 29 g) at 27oC and pressure 10 atm?
a) 0.48
b) 0.56
c) 0.64
d) 0.72
Answer
Answer: a [Reason:] Density of CO = 5*28/(0.0821*300) = 5.68 g/L, density of air = 10*29/(0.0821*300) = 11.77 g/L, => specific gravity = 5.68/11.77 = 0.48.
14. What is the compressibility factor for an ideal gas?
a) 1
b) 2
c) 3
d) Depends on the gas
Answer
Answer: a [Reason:] Compressibility of an ideal gas is always 1.
15. Which of the following is not the unit of R?
a) Atm.liter/K.mole
b) Pa.m3/K
c) N.Kg.m3/K.mole
d) None of the mentioned
Answer
Answer: c [Reason:] N.Kg.m/K.mole is the unit of R.
Set 5
1. How long would it take for a reversible process to complete?
a) Instant
b) Infinite
c) Depends on the process
d) None of the mentioned
Answer
Answer: b [Reason:] It takes infinite time for a reversible process to complete.
2. How long would it take for an irreversible process to complete?
a) Instant
b) Finite
c) Infinite
d) Cannot say
Answer
Answer: b [Reason:] It take a finite time for an irreversible process to complete.
3. Reversible process can be reversed by differential change in which of the following?
a) Temperature
b) Pressure
c) Volume
d) All of the mentioned
Answer
Answer: d [Reason:] Differential change in driving potential (dP, dV, dT, etc) can reverse a reversible process.
4. Which of the following a reversible process will involve?
a) Dissipative effects
b) Friction
c) Equilibrium transfer of energy
d) None of the mentioned
Answer
Answer: c [Reason:] Reversible process involves equilibrium transfer of energy.
5. Which of the following does both of the reversible and irreversible processes involve?
a) Increase molecular disorder
b) Dissipative effects
c) Friction
d) All of the mentioned
Answer
Answer: a [Reason:] Both reversible and irreversible processes increases molecular disorder.
6. Free expansion of gas with frictionless piston is example which process?
a) Reversible
b) Irreversible
c) Cannot say
d) None of the mentioned
Answer
Answer: a [Reason:] Free expansion of gas is reversible process.
7. Free expansion of gas against piston having friction is example of which process?
a) Reversible
b) Irreversible
c) Cannot say
d) None of the mentioned
Answer
Answer: b [Reason:] Free expansion of gas against piston having friction is irreversible process.
8. Mixing of dissimilar substances is example of which process?
a) Reversible
b) Irreversible
c) Cannot say
d) None of the mentioned
Answer
Answer: b [Reason:] Mixing of dissimilar substances is an irreversible process.
9. Change in phase is an example of which process?
a) Reversible
b) Irreversible
c) Cannot say
d) None of the mentioned
Answer
Answer: b [Reason:] Change in phase is an irreversible process.
10. Fluid flow through pipe is an example of which process?
a) Reversible
b) Irreversible
c) Cannot say
d) None of the mentioned
Answer
Answer: b [Reason:] Fluid flow through pipe is an irreversible process.
11. What is the work done by saturated water which evaporates to 10 kPa atmosphere to form 1 m3 of water vapor?
a) 1 kJ
b) -1 kJ
c) 10 kJ
d) -10 kJ
Answer
Answer: d [Reason:] Work done = -p∆V = -10*1 = -10 kJ.
12. What is the work done by saturated water which evaporates to 20 kPa atmosphere to form 1.5 m3 of water vapor?
a) 20 kJ
b) -20 kJ
c) 30 kJ
d) -30 kJ
Answer
Answer: d [Reason:] Work done = -p∆V = -20*1.5 = -30 kJ.
13. What is the work done by saturated water which evaporates to 1 kPa atmosphere to form 2 m3 of water vapor?
a) -2 kJ
b) 2 kJ
c) -1 kJ
d) 1 kJ
Answer
Answer: a [Reason:] Work done = -p∆V = -1*2 = -2 kJ.
14. What is the work done by 0.1 m3 saturated ethanol which evaporates to 10 kPa atmosphere to form 1 m3 of water vapor?
a) 9 kJ
b) -9 kJ
c) 10 kJ
d) -10 kJ
Answer
Answer: b [Reason:] Work done = -p∆V = -10*(1 – 0.1) = -9 kJ.
15. What is the work done by 0.5 m3 saturated ethanol which evaporates to 20 kPa atmosphere to form 2 m3 of water vapor?
a) 20 kJ
b) -20 kJ
c) 30 kJ
d) -30 kJ
Answer
Answer: d [Reason:] Work done = -p∆V = -20*(2 – 0.5) = -30 kJ.
