Chem 111 -final 2003
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Universal Science College (B. Sc. Biochemistry) I First Semester 2003 Subject: Physical Chemistry
Full Marks: 100 Pass Marks: 50 Time: 3 hours Group - A
1. a. b. c. d.
Answer any three questions. Questions are of equal value. 3 × 14=42 Derive kinetic gas equation stating the postulates on which it's derivation is based on .Calculate the temperature at which mean square velocity of SO2 molecule is equal to that of O2 molecules at 270C. What is transport number? State Hittorf's rule and explain the principle involved as well as experimental method applied for the determination of transport number by Hittorf's method. Discuss transition state theory of reaction rates. What do you understand by entropy? Derive an expression for the change in entropy with temperature and volume for an ideal gas. Calculate the entropy change involved in the isothermal reversible expansion of 1 moles of an ideal gas from a volume of 20 litres to a volume of 200 litres at 2000 C. Group B
2. a. b. c.
d. e. f. g. h.
Answer any six questions. Questions are of equal value. 6 × 7 = 42 Give the Maxwell-Boltzmann distribution law of molecular velocities and explain the terms involved in it. Also mention the significance of the law by graphical representation at different temperatures. What are lyophobic colloids? Write down various methods of preparation of lyophobic colloids. State and explain Kohlrausch's law. The equivalent ionic conductances of NaCl, NH4Cl and NaOH at infinite dilution are 126.5, 149.7 and 248.1 ohm-1 cm2 eqv-1 respectively. Calculate equivalent conductance at infinite dilution of NH4 OH. What are main assumptions of Debye-Huckel Onsagar theory of strong electrolytes? Explain how this theory accounts for the variation of the equivalent conductance with dilution. A first order reaction is 40% completed in 50 minutes. Calculate the value of the rate constant. In what time will the reaction be 80% completed? Define parallel reaction. How are rate constants in parallel reaction obtained? Derive an expression for entropy change of mixing of ideal gases. What are the conclusions drawn from it? Show the decrease in Helmholtz free energy at constant temperature gives the maximum work done by the system. Group – C
3. a. b. c. d. e.
Answer any eight questions. Questions are of equal value. 8 × 2 = 16 Write down vander waals equation of state and also mention the significance of the terms a and b. How does the dilution affect the molar and specific conductance of an electrolyte? What is zeta potential? Show your familiarity with the term 'gold number.' Calculate the kinetic energy of 1 molecule of N2 gas at 300 C given that R = 3.314 JK-1 mol-1.
f. g. h. i. j. k.
Define mean activity coefficient. Why higher order reactions are rare? Define consecutive reactive. Give an example of such reaction. What do you understand by instantaneous rate? How is it obtained? Prove that total entropy of the system and surrounding remains constant in a reversible process. State third law of thermodynamics.
l.
Derive conditions under which ∆G can be used as criteria for spontaneity of a process.
***
Universal Science College (B. Sc. Biochemistry) II First Semester 2003 Subject: Physical Chemistry
Full Marks: 100 Pass Marks: 50 Time: 3 hours Group - A
1. a. b.
c.
d.
Answer any three questions. Questions are of equal value. 3 × 14=42 Differenciate between lyophilic and lyophobic colloids. Mention various methods for the preparation of lyophobic colloids and their purification. What is the transference number of an anion? Show that the sum of transference number of cation and anion is equal to unity. Discuss the principle involved in determining transport number by Hittorf's method. Discuss Lindemann theory for unimolecular reaction. On the basis of this theory discuss how order of a gaseous reaction changes with pressure. For a certain reaction the values of the rate constants at 250 C and 850 C were found to be 3.46 x 10-5 and 4.87 x 10-3 respectively. Calculate the energy of activation. Establish the criteria for spontaneity of a process in terms of E,H,G, A and S. Calculate the increase in entropy in the evaporation of 2 mole of water at 373 K. Latent heat of vaporization of water is 2.20 KJ/gm. Group B
2. a.
b. c.
Answer any six questions. Questions are of equal value. 6 × 7 = 42 Derive vander waals' equation of state. One mole of diethyl ether occupies 15 litres volume at 2270 C. Calculate the pressure if vander waals constants for diethyl ether are: a = 17.38 atm litre2 mol-2 b = 0.134 litre mol-1 What are macromolecules? Describe the principle and method applied for the determination of average molecular weight of macromolecules by osmometry. Define activity coefficient. Show your awareness with ionic strength. Calculate the ionic strength of 0.1 M FeCl3 solution.
d.
e. f. g. h.
Show by necessary diagrammatic representation that loss in electrolytic concentration around electrode during electrolysis is directly proportional to the speed of migration of ions moving away from it. It is found that when NH4Cl solution is kept between electrodes with 25 cm apart and applied a potential difference of 15 volt, NH4+ traveled a distance of 1.64 cm in one hour. What is the mobility of NH4+ ion ? Define opposing reaction . Give examples of such reaction. Derive expression for rate constants in first order verses first order reaction. Derive an expression for rate constant of second order reaction involving two different reactants with different initial concentration. Also give an example of such reaction. Derive a clasius -claperyon equation. Also give the advantages of this equation. Calculate the free energy change accompanying the compression of 1 mole of CO2 at 570 c from 5 atmosphere to 100 atmosphere. Assume that CO2 behaves like an ideal gas. Group – C
3. a. b. c. d. e. f. g. h. i. j. k. l.
Answer any eight questions. Questions are of equal value. 8 × 2 = 16 What are various types of molecular velocities? Define most probable velocity. What is asymmetric effect? What are thixotropic gels? Give examples. Define electrophoresis. Mention its one application. How does the dilution effect the equivalent conductance of aqueous solutions of weak and strong electrolyte? Mention the significance of Debye-Hukel limiting equation. How is the rate of a reaction measured? Derive an expression for half life of a second order reaction. Define Parallel reaction. Give examples of such reaction. Calculate the entropy change for the fusion of 2 mole of a solid which melts at 300 K. The latent heat of fusion is 2.51 KJ mol-1. State Second law of thermodynamics. What is the advantage of 3rd law of thermodynamics? ***
Full Marks: 100 Pass Marks: 50 Time: 3 hours Group - A
1. a. b. c. d.
Answer any three questions. Questions are of equal value. 3 × 14=42 Derive kinetic gas equation stating the postulates on which it's derivation is based on .Calculate the temperature at which mean square velocity of SO2 molecule is equal to that of O2 molecules at 270C. What is transport number? State Hittorf's rule and explain the principle involved as well as experimental method applied for the determination of transport number by Hittorf's method. Discuss transition state theory of reaction rates. What do you understand by entropy? Derive an expression for the change in entropy with temperature and volume for an ideal gas. Calculate the entropy change involved in the isothermal reversible expansion of 1 moles of an ideal gas from a volume of 20 litres to a volume of 200 litres at 2000 C. Group B
2. a. b. c.
d. e. f. g. h.
Answer any six questions. Questions are of equal value. 6 × 7 = 42 Give the Maxwell-Boltzmann distribution law of molecular velocities and explain the terms involved in it. Also mention the significance of the law by graphical representation at different temperatures. What are lyophobic colloids? Write down various methods of preparation of lyophobic colloids. State and explain Kohlrausch's law. The equivalent ionic conductances of NaCl, NH4Cl and NaOH at infinite dilution are 126.5, 149.7 and 248.1 ohm-1 cm2 eqv-1 respectively. Calculate equivalent conductance at infinite dilution of NH4 OH. What are main assumptions of Debye-Huckel Onsagar theory of strong electrolytes? Explain how this theory accounts for the variation of the equivalent conductance with dilution. A first order reaction is 40% completed in 50 minutes. Calculate the value of the rate constant. In what time will the reaction be 80% completed? Define parallel reaction. How are rate constants in parallel reaction obtained? Derive an expression for entropy change of mixing of ideal gases. What are the conclusions drawn from it? Show the decrease in Helmholtz free energy at constant temperature gives the maximum work done by the system. Group – C
3. a. b. c. d. e.
Answer any eight questions. Questions are of equal value. 8 × 2 = 16 Write down vander waals equation of state and also mention the significance of the terms a and b. How does the dilution affect the molar and specific conductance of an electrolyte? What is zeta potential? Show your familiarity with the term 'gold number.' Calculate the kinetic energy of 1 molecule of N2 gas at 300 C given that R = 3.314 JK-1 mol-1.
f. g. h. i. j. k.
Define mean activity coefficient. Why higher order reactions are rare? Define consecutive reactive. Give an example of such reaction. What do you understand by instantaneous rate? How is it obtained? Prove that total entropy of the system and surrounding remains constant in a reversible process. State third law of thermodynamics.
l.
Derive conditions under which ∆G can be used as criteria for spontaneity of a process.
***
Universal Science College (B. Sc. Biochemistry) II First Semester 2003 Subject: Physical Chemistry
Full Marks: 100 Pass Marks: 50 Time: 3 hours Group - A
1. a. b.
c.
d.
Answer any three questions. Questions are of equal value. 3 × 14=42 Differenciate between lyophilic and lyophobic colloids. Mention various methods for the preparation of lyophobic colloids and their purification. What is the transference number of an anion? Show that the sum of transference number of cation and anion is equal to unity. Discuss the principle involved in determining transport number by Hittorf's method. Discuss Lindemann theory for unimolecular reaction. On the basis of this theory discuss how order of a gaseous reaction changes with pressure. For a certain reaction the values of the rate constants at 250 C and 850 C were found to be 3.46 x 10-5 and 4.87 x 10-3 respectively. Calculate the energy of activation. Establish the criteria for spontaneity of a process in terms of E,H,G, A and S. Calculate the increase in entropy in the evaporation of 2 mole of water at 373 K. Latent heat of vaporization of water is 2.20 KJ/gm. Group B
2. a.
b. c.
Answer any six questions. Questions are of equal value. 6 × 7 = 42 Derive vander waals' equation of state. One mole of diethyl ether occupies 15 litres volume at 2270 C. Calculate the pressure if vander waals constants for diethyl ether are: a = 17.38 atm litre2 mol-2 b = 0.134 litre mol-1 What are macromolecules? Describe the principle and method applied for the determination of average molecular weight of macromolecules by osmometry. Define activity coefficient. Show your awareness with ionic strength. Calculate the ionic strength of 0.1 M FeCl3 solution.
d.
e. f. g. h.
Show by necessary diagrammatic representation that loss in electrolytic concentration around electrode during electrolysis is directly proportional to the speed of migration of ions moving away from it. It is found that when NH4Cl solution is kept between electrodes with 25 cm apart and applied a potential difference of 15 volt, NH4+ traveled a distance of 1.64 cm in one hour. What is the mobility of NH4+ ion ? Define opposing reaction . Give examples of such reaction. Derive expression for rate constants in first order verses first order reaction. Derive an expression for rate constant of second order reaction involving two different reactants with different initial concentration. Also give an example of such reaction. Derive a clasius -claperyon equation. Also give the advantages of this equation. Calculate the free energy change accompanying the compression of 1 mole of CO2 at 570 c from 5 atmosphere to 100 atmosphere. Assume that CO2 behaves like an ideal gas. Group – C
3. a. b. c. d. e. f. g. h. i. j. k. l.
Answer any eight questions. Questions are of equal value. 8 × 2 = 16 What are various types of molecular velocities? Define most probable velocity. What is asymmetric effect? What are thixotropic gels? Give examples. Define electrophoresis. Mention its one application. How does the dilution effect the equivalent conductance of aqueous solutions of weak and strong electrolyte? Mention the significance of Debye-Hukel limiting equation. How is the rate of a reaction measured? Derive an expression for half life of a second order reaction. Define Parallel reaction. Give examples of such reaction. Calculate the entropy change for the fusion of 2 mole of a solid which melts at 300 K. The latent heat of fusion is 2.51 KJ mol-1. State Second law of thermodynamics. What is the advantage of 3rd law of thermodynamics? ***
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