Rr221801-thermodynamics-and-kinetics

Set No. 1

Code No: RR221801

II B.Tech Supplimentary Examinations, Aug/Sep 2008 THERMODYNAMICS AND KINETICS (Metallurgy & Material Technology) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) Name the following systems with proper explanation. i. A container having water and ice exchanging heat with surrounding. ii. A system consisting of sugar in water. iii. A system consisting of air in a closed container having perfectly insulated walls. (b) Bring out the differences among the following. i. Thermodynamic system ii. Thermodynamic process iii. Thermodynamic cycle.

[8+8]

2. (a) Show that internal energy is function of temperature only. (b) The internal energy of a closed system is given by U = 100 + 50T + 0.04T 2 in Joules. The heat absorbed Q = 4000 + 16T in joules.(T is in Kelvin). If the system changes from 500 K to 1000K, what is the work done. (c) Calculate the work transfer and change in internal energy if the gas is changing it’s state from 1 bar, 270 C to 20 bar, 4000 C polytropically. [6+6+4]   = ∆v 3. (a) Show that d (∆H) dp s

(b) Name the intensive and extensive parameters in the entropy representation. Explain them (c) The entropy of a hot baked potato decreases as it cools. Is this a violation of the increase of entropy principle? Explain. [5+5+6] 4. (a) Explain the applications of Boltzmann equation. (b) Explain the differences between classical thermodynamics and statistical thermodynamics. [8+8] 5. (a) Define Helmholtz energy function and explain its significance. (b) Derive the relationship between the standard free energy change and the equilibrium constant of a reaction. [8+8] 6. (a) Discuss the importance of sigma function in evaluation of fugacity. (b) Explain the effect of temperature on equillibrium constant. (c) How is equillibrium constant determined at any time. 1 of 2

[6+5+5]

Set No. 1

Code No: RR221801 7. (a)

i. Does the Clapeyron equation involve any approximation, or is it exact? ii. What approximation are involved in the Clapeyron -clasius equation.

(b) What is Clapeyron equation? What assumptions are made in obtaining the Classius-Clapeyron equation from Clapeyron equation? [8+8] 8. (a) The gas phase reaction of nitric oxide and Bromine Yields NOBr. 2 N O(g) + Br2 → 2 N OBr(g). The rate law is = K[N O]2 [Br2 ]. What is the reaction order with respect to the each of the reactants, and what is the overall reaction order? (b) The gas phase reaction of Hydrogen and Iodine monochloride, H2 (g) + 2 ICl(g) → 2 Hcl(g) + I2 (g) is first order in H2 and first order in Icl. What is the rate law, and what are the units of the rate constant. [8+8] ⋆⋆⋆⋆⋆

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Set No. 2

Code No: RR221801

II B.Tech Supplimentary Examinations, Aug/Sep 2008 THERMODYNAMICS AND KINETICS (Metallurgy & Material Technology) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) State the essence of the four laws of thermodynamics. (b) What are the various approaches adopted in the study of thermodynamics and which approach is adopted in the study of classical thermodynamics. (c) What is a thermodynamic system and explain what is meant by surroundings and universe? (d) What is a point function? Give some examples which are not point functions. [16] 2. (a) Derive an expression for the work done in isothermal process. (b) calculate the work done when a gas of ‘n’ moles is i. expanded to twice the original volume ii. compressed to half its original volume isothermally at temperature ‘T’. [8+8] 3. (a) Prove that ∆G0 = RT ℓnK. (b) A gas turbine is to operate wth an inlet pressure and temperature of 6 bar and 800 k. The outlet pressure and temperature are 1.0 bar and 500 k. The turbine loses 25 kJ/kg to the surrounding. If surrounding temperature is 300 k. calculate decrease in availability and irreversibility. [8+8] 4. (a) What is Nernst heat theorem. Define and explain the theorem with the help of relevant equation. (b) What is entropy generation? Can the entropy generation be negative? Explain. [10+6] 5. (a) Explain the differences between Gibb’s -Duhem equation and Gibb’s - Helmholtz equation. (b) What is the purpose of free energy functions and give the significance of these functions. [8+8] 6. (a) Define and explain the following terms i. Fugacity ii. Activity iii. Equilibrium constant

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Set No. 2

Code No: RR221801

(b) Find the equilibrium constant for N H3 synthesis reaction at 600k and 800k using the following data (assume any missing data) ∆H o 298k = −46, 190 J/gm/mol ∆Goo 298k = −16, 635 J/gm/mol ∆Cpo = −31, 780 + 35.517 × 10−3 T − 9.316 × 10−6 T 2 Cp injoules/gm/mol; T in 0 k. 7. (a)

[6+10]

i. Does the Clapeyron equation involve any approximation, or is it exact? ii. What approximation are involved in the Clapeyron -clasius equation.

(b) What is Clapeyron equation? What assumptions are made in obtaining the Classius-Clapeyron equation from Clapeyron equation? [8+8] 8. (a) The gas phase reaction of nitric oxide and Bromine Yields NOBr. 2 N O(g) + Br2 → 2 N OBr(g). The rate law is = K[N O]2 [Br2 ]. What is the reaction order with respect to the each of the reactants, and what is the overall reaction order? (b) The gas phase reaction of Hydrogen and Iodine monochloride, H2 (g) + 2 ICl(g) → 2 Hcl(g) + I2 (g) is first order in H2 and first order in Icl. What is the rate law, and what are the units of the rate constant. [8+8] ⋆⋆⋆⋆⋆

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Set No. 3

Code No: RR221801

II B.Tech Supplimentary Examinations, Aug/Sep 2008 THERMODYNAMICS AND KINETICS (Metallurgy & Material Technology) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) Derive an expression relating the volume and the pressure of the gas with the number of molecules and their velocities. (b) Discuss the method of determination of the most probable macrostate with in a given system. [10+6] 2. (a) State the first law of thermodynamics and show how it defines internal energy as a property. (b) State and explain Kirchoff’s law.

[8+8]

3. (a) Discuss the second law of thermodynamics using classical viewpoint. How is entropy defined in this approach? Can the entropy of a system decrease? Explain. (b) Calculate standard entropy of a metal at 6500 C if its entropy at 270 C = 5 Cal/gm/mole and Cp = 5.4 + 1.2 × 10−3 T Cal/gm/mole. [8+8] 4. (a) What is Nernst heat theorem. Define and explain the theorem with the help of relevant equation. (b) What is entropy generation? Can the entropy generation be negative? Explain. [10+6] 5. (a) Explain the differences between Gibb’s -Duhem equation and Gibb’s - Helmholtz equation. (b) What is the purpose of free energy functions and give the significance of these functions. [8+8] 6. (a) What is meant by the ‘standard free energy change’ of a reaction? Derive an expression relating it to the equilibrium constant of the reaction. (b) What is the significance of the sign of free energy change?

[10+6]

7. (a) From the Classius-Clapeyron equation, derive the following expression for the vapor pressure of liquid metal. + B where A and B are constants. Log P = A T (b) The vapor pressure ‘p’ of liquid A is given by log P (mm) = −2450 + 6.69 and T that of solid A by log P(mm) =-6947 + 10.8 Calculate the temperature at which liquid and solid will have the same vapour pressure. [10+6]

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Set No. 3

Code No: RR221801

8. (a) Define the term ‘specific reaction rate constant’. From consideration of the theory of absolute reaction rates, derive an expression for the specific reaction rate constant of a reaction. (b) Explain the kinetic equation for first order reaction. ⋆⋆⋆⋆⋆

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[8+8]

Set No. 4

Code No: RR221801

II B.Tech Supplimentary Examinations, Aug/Sep 2008 THERMODYNAMICS AND KINETICS (Metallurgy & Material Technology) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) Derive an expression for Boyle temperature in terms of vanderwall’s constants. (b) Explain the term ‘internal energy’ of a system. (c) Calculate the increase in internal energy of a gaseous system at a constant pressure of one atmosphere when 10 calories of heat (or energy) are added and the volume of the system increases by 1000 C. [6+4+6] 2. (a) State HESS’s law and explain with an example. (b) Calculate the work done by an ideal gas when it expands from 5bar, 3500 K to 2 bar 300K, mass of air is 1.0kg. Expansion is adiabatic. (c) How would you determine experimentally the heat of formation of compound? Explain briefly. [4+6+6] heating

−−−−→ 3. (a) Prove that for a reaction Liquid , gas ←−−−− cooling

dp.V gas = dt(Sgas − Sliquid ) (b) Explain Gibb’s definition of entropy in detail.

[8+8]

4. (a) What is Nernst heat theorem. Define and explain the theorem with the help of relevant equation. (b) What is entropy generation? Can the entropy generation be negative? Explain. [10+6] 5. (a) Explain the differences between Gibb’s -Duhem equation and Gibb’s - Helmholtz equation. (b) What is the purpose of free energy functions and give the significance of these functions. [8+8] 6. (a) Discuss the importance of sigma function in evaluation of fugacity. (b) Explain the effect of temperature on equillibrium constant. (c) How is equillibrium constant determined at any time.

[6+5+5]

7. (a) Derive Clausius-Clapeyron equation starting from fundamentals. State the conditions under which approximation is valid. (b) Prove that violation of the Kelvin-Planck statement leads to violation of the Clausius statement of the second law of thermodynamics. [8+8] 1 of 2

Set No. 4

Code No: RR221801

8. (a) Explain the standard free energy change for any reaction. (b) Determine the equillibrium constant at 250 C for the reaction. CH4 (g) + H2 O(ℓ) → CO(g) + 3H2 (g). [6+10] Data Component ∆0 G at 250 C CO (g) - 137.8 KJ/mole CH4 (g) - 50.09 KJ/mole H2 O(l) - 238.0 KJ/mole ⋆⋆⋆⋆⋆

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