Code No: NR220802
NR
Set No. 2
in
II B.Tech II Semester Examinations,APRIL 2011 CHEMICAL ENGINEERING THERMODYNAMICS Chemical Engineering Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ????? 1. (a) Write different causes of irreversibility. Why cooling of hot coffee is an irreversible process [8+8]
ld .
(b) Discuss different difficulties in producing ideal heat engine.
2. (a) Generally we assume that steam can be modeled as an ideal gas. Find the range of pressure where this model holds good.
or
(b) In predicting pressures with an accuracy of 2%, a Van der Waals gas is treated as an ideal gas. Find the region of p-v-T surface in which the above approximation is valid. [8+8] 3. (a) Define reduced temperature, pressure and density.
[4]
(b) Air obeying ideal gas law undergoes a change of state from P1 =1 atm, V1 =10 m3 , to P2 = 10 atm and 0.1 m3 by the following reversible processes:
[12]
4. (a) What is internal energy of a substance? Explain briefly.
[4]
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i. Compression at constant temperature. ii. Adiabatic compression followed by isobaric cooling. iii. Isochoric heating followed by isobaric cooling.
(b) Liquid water at 1800 C and 1,002.7 kPa has an internal energy (on an arbitrary scale) of 762.0 kJ/kg and a specific volume of 1.128 cm3 /g.
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i. What is its enthalpy? ii. The water is brought to the vapor state at 3000 C and 1,500 kPa, where its internal energy is 2,784.4 kJ/kg and its specific volume is 169.7 cm3 /g. Calculate ∆U and ∆H for the process. [12]
Aj
5. A lump of copper having a mass of 5kg at a temperature of 5400 C is dropped into a well-insulated bucket containing 50kg of water at a temperature of 200 C. If the specific heats of copper and water are 0.418KJ/kg 0 C and 4.4KJ/kg 0 C respectively, calculate the resulting changes in entropy of the water and copper, and calculate the total entropy change resulting from the process. [16] 6. The piston of a piston cylinder device containing a gas has a mass of 75 Kg. Diameter of piston is 250 mm. The local atmospheric pressure is 0.97 bar gravitational acceleration is 9.8 m/second square. [16] (a) Determine the pressure inside the cylinder. 1
Code No: NR220802
NR
Set No. 2
(b) If some heat is transferred and its volume doubles, do you expect the pressure inside the cylinder to change? 7. A reversible compressor of 1 mol of an ideal gas in a piston / cylinder device results in a pressure increase from 1 bar to P2 and a temperature increase from 400 K to 950 K. The path followed by the gas during compression is given by; And the molar heat capacity of the gas is given by CP / R = 3.85 + 0.57×10−3 T
[ T in Kelvin ]
in
P V 1.55 = constant.
[16]
ld .
Determine the heat transferred during the process and the final pressure.
8. (a) A gas mixture consisting of 20% ethane and 80% oxygen at 298K is burned completely after diluting it with double the volume of CO2 at the same temperature 298K. The mean heat capacities is (J/mol.K) are 54.56 for CO2 , 43.02 for water vapour, and 35.52 for O2 . The standard heat of reaction of ethane at 298K is (-1478) kJ/mol. Determine the theoretical flame temperature. [12]
or
(b) What is the necessity of standard states for calculations involving heat effects. [4]
Aj
nt
uW
?????
2
Code No: NR220802
NR
Set No. 4
in
II B.Tech II Semester Examinations,APRIL 2011 CHEMICAL ENGINEERING THERMODYNAMICS Chemical Engineering Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ?????
ld .
1. A reversible compressor of 1 mol of an ideal gas in a piston / cylinder device results in a pressure increase from 1 bar to P2 and a temperature increase from 400 K to 950 K. The path followed by the gas during compression is given by; P V 1.55 = constant.
And the molar heat capacity of the gas is given by CP / R = 3.85 + 0.57×10−3 T
[ T in Kelvin ]
[16]
or
Determine the heat transferred during the process and the final pressure.
2. (a) Generally we assume that steam can be modeled as an ideal gas. Find the range of pressure where this model holds good.
uW
(b) In predicting pressures with an accuracy of 2%, a Van der Waals gas is treated as an ideal gas. Find the region of p-v-T surface in which the above approximation is valid. [8+8] 3. (a) Define reduced temperature, pressure and density.
[4]
(b) Air obeying ideal gas law undergoes a change of state from P1 =1 atm, V1 =10 m3 , to P2 = 10 atm and 0.1 m3 by the following reversible processes:
nt
i. Compression at constant temperature. ii. Adiabatic compression followed by isobaric cooling. iii. Isochoric heating followed by isobaric cooling.
[12]
4. (a) Write different causes of irreversibility. Why cooling of hot coffee is an irreversible process (b) Discuss different difficulties in producing ideal heat engine.
[8+8]
Aj
5. A lump of copper having a mass of 5kg at a temperature of 5400 C is dropped into a well-insulated bucket containing 50kg of water at a temperature of 200 C. If the specific heats of copper and water are 0.418KJ/kg 0 C and 4.4KJ/kg 0 C respectively, calculate the resulting changes in entropy of the water and copper, and calculate the total entropy change resulting from the process. [16] 6. The piston of a piston cylinder device containing a gas has a mass of 75 Kg. Diameter of piston is 250 mm. The local atmospheric pressure is 0.97 bar gravitational acceleration is 9.8 m/second square. [16] (a) Determine the pressure inside the cylinder. 3
NR
Code No: NR220802
Set No. 4
(b) If some heat is transferred and its volume doubles, do you expect the pressure inside the cylinder to change? 7. (a) What is internal energy of a substance? Explain briefly.
[4]
0
(b) Liquid water at 180 C and 1,002.7 kPa has an internal energy (on an arbitrary scale) of 762.0 kJ/kg and a specific volume of 1.128 cm3 /g.
in
i. What is its enthalpy? ii. The water is brought to the vapor state at 3000 C and 1,500 kPa, where its internal energy is 2,784.4 kJ/kg and its specific volume is 169.7 cm3 /g. Calculate ∆U and ∆H for the process.
ld .
[12]
or
8. (a) A gas mixture consisting of 20% ethane and 80% oxygen at 298K is burned completely after diluting it with double the volume of CO2 at the same temperature 298K. The mean heat capacities is (J/mol.K) are 54.56 for CO2 , 43.02 for water vapour, and 35.52 for O2 . The standard heat of reaction of ethane at 298K is (-1478) kJ/mol. Determine the theoretical flame temperature. [12] (b) What is the necessity of standard states for calculations involving heat effects. [4]
Aj
nt
uW
?????
4
Code No: NR220802
NR
Set No. 1
in
II B.Tech II Semester Examinations,APRIL 2011 CHEMICAL ENGINEERING THERMODYNAMICS Chemical Engineering Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ?????
ld .
1. A reversible compressor of 1 mol of an ideal gas in a piston / cylinder device results in a pressure increase from 1 bar to P2 and a temperature increase from 400 K to 950 K. The path followed by the gas during compression is given by; P V 1.55 = constant.
And the molar heat capacity of the gas is given by CP / R = 3.85 + 0.57×10−3 T
[ T in Kelvin ]
Determine the heat transferred during the process and the final pressure.
or
2. (a) Define reduced temperature, pressure and density.
[16] [4]
(b) Air obeying ideal gas law undergoes a change of state from P1 =1 atm, V1 =10 m3 , to P2 = 10 atm and 0.1 m3 by the following reversible processes:
uW
i. Compression at constant temperature. ii. Adiabatic compression followed by isobaric cooling. iii. Isochoric heating followed by isobaric cooling.
[12]
3. A lump of copper having a mass of 5kg at a temperature of 5400 C is dropped into a well-insulated bucket containing 50kg of water at a temperature of 200 C. If the specific heats of copper and water are 0.418KJ/kg 0 C and 4.4KJ/kg 0 C respectively, calculate the resulting changes in entropy of the water and copper, and calculate the total entropy change resulting from the process. [16]
nt
4. The piston of a piston cylinder device containing a gas has a mass of 75 Kg. Diameter of piston is 250 mm. The local atmospheric pressure is 0.97 bar gravitational acceleration is 9.8 m/second square. [16] (a) Determine the pressure inside the cylinder.
Aj
(b) If some heat is transferred and its volume doubles, do you expect the pressure inside the cylinder to change?
5. (a) What is internal energy of a substance? Explain briefly.
[4]
(b) Liquid water at 1800 C and 1,002.7 kPa has an internal energy (on an arbitrary scale) of 762.0 kJ/kg and a specific volume of 1.128 cm3 /g. i. What is its enthalpy? ii. The water is brought to the vapor state at 3000 C and 1,500 kPa, where its internal energy is 2,784.4 kJ/kg and its specific volume is 169.7 cm3 /g. Calculate ∆U and ∆H for the process. 5
Code No: NR220802
NR
Set No. 1 [12]
6. (a) Generally we assume that steam can be modeled as an ideal gas. Find the range of pressure where this model holds good.
in
(b) In predicting pressures with an accuracy of 2%, a Van der Waals gas is treated as an ideal gas. Find the region of p-v-T surface in which the above approximation is valid. [8+8]
ld .
7. (a) A gas mixture consisting of 20% ethane and 80% oxygen at 298K is burned completely after diluting it with double the volume of CO2 at the same temperature 298K. The mean heat capacities is (J/mol.K) are 54.56 for CO2 , 43.02 for water vapour, and 35.52 for O2 . The standard heat of reaction of ethane at 298K is (-1478) kJ/mol. Determine the theoretical flame temperature. [12] (b) What is the necessity of standard states for calculations involving heat effects. [4]
or
8. (a) Write different causes of irreversibility. Why cooling of hot coffee is an irreversible process (b) Discuss different difficulties in producing ideal heat engine.
Aj
nt
uW
?????
6
[8+8]
Code No: NR220802
NR
Set No. 3
in
II B.Tech II Semester Examinations,APRIL 2011 CHEMICAL ENGINEERING THERMODYNAMICS Chemical Engineering Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ?????
ld .
1. A reversible compressor of 1 mol of an ideal gas in a piston / cylinder device results in a pressure increase from 1 bar to P2 and a temperature increase from 400 K to 950 K. The path followed by the gas during compression is given by; P V 1.55 = constant.
And the molar heat capacity of the gas is given by CP / R = 3.85 + 0.57×10−3 T
[ T in Kelvin ]
Determine the heat transferred during the process and the final pressure.
[16]
or
2. (a) Generally we assume that steam can be modeled as an ideal gas. Find the range of pressure where this model holds good.
uW
(b) In predicting pressures with an accuracy of 2%, a Van der Waals gas is treated as an ideal gas. Find the region of p-v-T surface in which the above approximation is valid. [8+8] 3. The piston of a piston cylinder device containing a gas has a mass of 75 Kg. Diameter of piston is 250 mm. The local atmospheric pressure is 0.97 bar gravitational acceleration is 9.8 m/second square. [16] (a) Determine the pressure inside the cylinder. (b) If some heat is transferred and its volume doubles, do you expect the pressure inside the cylinder to change?
nt
4. (a) Write different causes of irreversibility. Why cooling of hot coffee is an irreversible process (b) Discuss different difficulties in producing ideal heat engine.
[8+8]
Aj
5. (a) A gas mixture consisting of 20% ethane and 80% oxygen at 298K is burned completely after diluting it with double the volume of CO2 at the same temperature 298K. The mean heat capacities is (J/mol.K) are 54.56 for CO2 , 43.02 for water vapour, and 35.52 for O2 . The standard heat of reaction of ethane at 298K is (-1478) kJ/mol. Determine the theoretical flame temperature. [12] (b) What is the necessity of standard states for calculations involving heat effects. [4]
6. (a) Define reduced temperature, pressure and density.
[4]
(b) Air obeying ideal gas law undergoes a change of state from P1 =1 atm, V1 =10 m3 , to P2 = 10 atm and 0.1 m3 by the following reversible processes: 7
Code No: NR220802
NR
Set No. 3
i. Compression at constant temperature. ii. Adiabatic compression followed by isobaric cooling. iii. Isochoric heating followed by isobaric cooling.
[12]
8. (a) What is internal energy of a substance? Explain briefly.
in
7. A lump of copper having a mass of 5kg at a temperature of 5400 C is dropped into a well-insulated bucket containing 50kg of water at a temperature of 200 C. If the specific heats of copper and water are 0.418KJ/kg 0 C and 4.4KJ/kg 0 C respectively, calculate the resulting changes in entropy of the water and copper, and calculate the total entropy change resulting from the process. [16] [4]
ld .
(b) Liquid water at 1800 C and 1,002.7 kPa has an internal energy (on an arbitrary scale) of 762.0 kJ/kg and a specific volume of 1.128 cm3 /g.
or
i. What is its enthalpy? ii. The water is brought to the vapor state at 3000 C and 1,500 kPa, where its internal energy is 2,784.4 kJ/kg and its specific volume is 169.7 cm3 /g. Calculate ∆U and ∆H for the process.
Aj
nt
uW
?????
8
[12]
