thermodynamics- old papers- jntu question papers

Code No: R050211802 Set No. 1
II B.Tech I Semester Regular Examinations, November 2007
THERMODYNAMICS AND KINETICS
(Metallurgy & Material Technology)
Time: 3 hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks
⋆ ⋆ ⋆ ⋆ ⋆
1. (a) Prove the following for a closed system .
For constant volume process Q = mCv (T2 − T1)
For constant pressure process Q =mCp (T2 − T1)
(b) Dierentiate between intensive and extensive properties with examples. [12+4]
2. (a) Claculate the work done for the following reversible process
i. Isobaric
ii. Adiabatic
(b) What are point and path functions ? Give some examples [8+8]
3. (a) Show that d
H
dp  s =
v
(b) Name the intensive and extensive parameters in the entropy representation .
Explain them.
(c) The entropy of hot baked potato decreases as it cools . is this a violation of
the increases of entropy principle ? Explain. [16]
4. (a) Explain the following
i. Gibb’s free energy
ii. Helmholtz function
(b) Prove thatW=n! / (n0! n1! n2!) WhereWis maximum possible arrangements.
[16]
5. (a) State and explain the third law of thermodynamics .what is its importance.
[6]
(b) Derive an expression to show variation of equilibrium constant with tempera-
ture. [10]
6. (a) What the relation between free energy and equilibrium constant for any reac-
tion and explain.
(b) At equilibrium of any reaction what is the relation of free energy change and
equilibrium constant and explain. [16]
7. (a) Explain the Duhrings rule and its importance.
(b) Explain the Truton’s rule and its importance. [16]
8. (a) Explain Zero order reaction.

(b) Explain collision theory of chemical reaction. [16]



Code No: R050211802 Set No. 2
II B.Tech I Semester Regular Examinations, November 2007
THERMODYNAMICS AND KINETICS
(Metallurgy & Material Technology)
Time: 3 hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks
⋆ ⋆ ⋆ ⋆ ⋆
1. (a) State and explain Zeroth law of thermodynamics.
(b) Distinguish clearly between integral and excess thermodynamic properties.
(c) Explain the limitations of thermodynamics. [6+5+5]
2. (a) Show that internal energy is a function of temperature only.
(b) The internal energy of a closed system is given by U = 100 + 50T+ 0.04T2
in Joules. The heat absorbed Q = 4000 +16T in Joules. ( T is in Kelvin ). If
the system changes from 500 K to 1000 K, what did the work done.
(c) Calculate the work transfer and change in internal energy if the gas is changing
its state from 1 bar, 270 to 20 bar, 4000 C polytropically. [6+6+6]
3. (a) Explain and discuss the importance of Second law of thermodynamics.
(b) i. Eciency of a cyclic process and
ii. Carnot theorem. [8+8]
4. (a) Explain the following
i. Gibb’s free energy
ii. Helmholtz function
(b) Prove thatW=n! / (n0! n1! n2!) WhereWis maximum possible arrangements.
[16]
5. (a) State and explain the third law of thermodynamics .what is its importance.
[6]
(b) Derive an expression to show variation of equilibrium constant with tempera-
ture. [10]
6. (a) ‘Fugacity of a component is equal to its activity for ideal solution’. Say true
or false and explain why is it so.
(b) Derive an expression for the change in the free energy when 1gram mole of a
pure substance goes in solution. [16]
7. (a) Explain the Duhrings rule and its importance.
(b) Explain the Truton’s rule and its importance. [16]
8. (a) Explain the standard free energy change for any reaction. [6]
(b) Determine the equilibrium constant at 250c for the reaction
CH4(g) + H2O(l) ! CO(g) + 3H2(g)
Data: [10]
COMPONENT
0G at 250c
CO(g) -137.8 KJ/mole
CH4 (g) -50.09 KJ/mole
H2O (1) -238.0 KJ/mole


Code No: R050211802 Set No. 3
II B.Tech I Semester Regular Examinations, November 2007
THERMODYNAMICS AND KINETICS
(Metallurgy & Material Technology)
Time: 3 hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks
⋆ ⋆ ⋆ ⋆ ⋆
1. Define the following :
(a) Extensive property
(b) Charle’s law
(c) State property
(d) Critical temperature. [16]
2. (a) State alternative statement of the first law of thermodynamics .
(b) One mole of an ideal gas expands reversibly and isothermally from an initial
volume of V1 to the final volume of 10V1. During expansion the work done by
the system is 42kJ. If the final pressure is 100 bar, then calculate V1.
(c) What is an adiabatic process and what is an adiabatic system. [4+8+4]
3. (a) Is a process internally reversible and adiabatic, necessarily isocentropic? Ex-
plain.
(b) What is meant by the standard molar entropy of a substance? how are stan-
dard molar entropy are used to calculate the standard entropies of a reactions?
(c) Why are standard molar entropies some times called absolute entropires? Ex-
plain. [16]
4. (a) Explain the deductions of third law of thermodynamics
(b) Explain various methods of calculatation of
SO for a chemical reaction [16]
5. (a) State and explain the third law of thermodynamics .what is its importance.
[6]
(b) Derive an expression to show variation of equilibrium constant with tempera-
ture. [10]
6. (a) What the relation between free energy and equilibrium constant for any reac-
tion and explain.
(b) At equilibrium of any reaction what is the relation of free energy change and
equilibrium constant and explain. [16]
7. (a) From the classius clapeyron equation, derive the following.
Expression for the vapor pressure of liquid metal
Log P=A/T+B where A and B are constants.
(b) The vapor pressure P of liquid A is given by Log P (mm) = -2450/T +6.69
abd that of a solid A by log P(mm)=6947+10.8. Calculate the temperature
at which liquid and solid will have the same vapor pressure. [16]
8. (a) Bring out the important characteristic of a catalyst and explain its action.
(b) Explain the various factors aecting the rate of reaction. [16]
Code No: R050211802 Set No. 4
II B.Tech I Semester Regular Examinations, November 2007
THERMODYNAMICS AND KINETICS
(Metallurgy & Material Technology)
Time: 3 hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks
⋆ ⋆ ⋆ ⋆ ⋆
1. (a) Name few macroscopic modes of energy and a few microscopic modes of energy.
(b) Distingush between study state and equilibrium.
(c) State and explain the criteria which the system should satisfy for it to be in
a thermodynamic equilibrium. [6+5+5]
2. (a) Distinguish between ‘Enthalpy’ and ‘heat capacity’
(b) A student made the following erroneous statement in a laboratory report on
Bomb Calorimetry.
“
H =
E + P
V. Since the bomb calorimetry process is a constant vol-
ume one,
V = 0 and
E =
H. Explain in detail why this arrangement is
incorrect. [6+10]
3. Calculate the standard entropy of a pure iron at 16270C if it’s standard entropy
at 250C is 6.50 Cal / deg / mole. The phase transformation in pure iron may be
represented as follows : [16]
< α−Fe >!< β −Fe >! 9100c < γ −Fe >! 14000c < δ−Fe >! 15390c{Fe}
Given data:
Cp, < α − Fe >= 4.18 + 5.9210−3 T cal/deg/mole
Cp, < β − Fe > = 9.0 cal/deg/mole
Cp, < γ − Fe >= 1.84 + 4.6610−3 T cal/deg/mole
Cp, < δ − Fe > = 10.50 cal/deg/mole
Cp, {Fe} = 10.0 cal/deg/mole
< α − Fe >!< β − Fe >;
H0
7600c = 660 cal/ mole
< β − Fe >!< γ − Fe >;
H0
9100c = 215 cal/mole
< γ − Fe >!< δ − Fe >;
H0
14000c = 165 cal/ mole
< δ − Fe >! {Fe};
H0
15390c = 3670 cal/mole
4. (a) What do you understand by the term free energy of a system. what is its
Significance?
(b) From the first principles, derive the equations for the Gibbs free energy
G =

H − T
S
(c) How can free energy change of a reaction determine experimentally. [16]
5. (a) What do you know about thermo chemical data. [8]
(b) Discuss the use of third law of thermodynamics in evolution of
SO of a
reaction [8]
6. (a) Derive Van ‘tho’s equation for the variation with temperature of equilibrium
constant.
(b) Explain how standard free energy of reaction related to the equilibrium con-
stant of a reaction. [16]
7. (a) Say true or false the following statements with suitable Explanation. Activity
of component can never be greater then unity in a system under equilibrium.
(b) State and explain Troutons rule. [16]
8. (a) Derive an expression for the rate constant of a first order reaction
(b) Discuss the importance of equilibrium constant and its eects on equilibrium
conversion. [16]