chemistry Honours(H3) 2st sem 2016 previous year BSc question paper | Assam University
TDC Even Semester Exam., 2016
CHEMISTRY
Honours
(2nd Semester)
Paper No. : CHMH-203
(Physical Chemistry)
Full Marks: 35
Pass Marks: 12
Time: 2 hours
The figures in the margin indicate frill marks for the questions
Answer five questions, selecting one from each Unit
UNIT I
1. (a) Discuss in detail Maxwell’s distribution of molecular velocities. 4
(b) For hydrogen gas, calculate the (i) root- mean-square velocity, (ii) average velocity and (iii) most probable velocity at 0 °C. 1±1±1=3
2. (a) Show that the most probable kinetic energy is given by RT/2 per mole and average kinetic energy is given by 3RT/ 2 per mole. 3
(b) Explain the following terms:
(i) Collision diameter
(ii) Collision number
(iii) Collision cross-section
(iv) Collision frequency
(c) Show that the mean free path of a gas molecule increases by decrease in pressure.
UNIT—lI
3. (a) Derive the Freuiidlich ad3orption isotherm from the Gibbs adsorption isotherm s applied to a gas.
(b) Explain the effect of temperature and pressure on adosorptiofl.
(c) At 0 °C and 1 atm pressure, the volume of nitrogen gas required to cover a sample of silica gel with monomolecular layer is found to be 130 cm3 g1 of the gel. Calculate the surface area per gram of silica geL Givcn, arca occupied by a nitrogen molecule is 0162 (nm)2.
4. (a) Discuss briefly BET theory of multilayer adsorption.
(b) Show that when a diatomic gas adsorbs as atoms on the surface of a solid, the Langmuir adsorption isotherm becomes O(K/[1+(K11 where the symbols have their usual meanings.
UNIT—Ill
5. (a) Derive the relation between enthalpy of reaction of constant volume and at constant pressure. 3
(b) How would you determine (i) enthalpics of reactions and (ii) enthalpies of formation of compounds from bond energies? 2+24
6. (a) Derive Kirchhoff’s equation depicting the variation of enthalpy of reaction with temperature. Write down the integrated form of the equation.. 4+1=5
(b) Calculate the enthalpy of formation of OHe ions at 25 °C from the following thermochemical data: 2 H2O) _,He(aqj+OHe(agj; iH°=573 kJ H2(g)+.O2(g)-4H2O); AH°=-285•9kJ
UNIT—IV
7. (a) Discuss the variation of mutual miscibility of phenol-water system with variation of temperature.
(b) State and explain Raoult’s law and Henry’s law. Show that if in any solution, the solvent obeys Raoult’s law, the solute oJ,eys Henry’s law.
8. (a) Derive GibbsDuhem.MarW1leS equation. Show that if in a binary solution, component A obeys Raoult’s law; Ui component B would also obey Raoult’s law. I
(b) The Henry’s law constant for H2 (g) in water is 534 x107 solubilty of this gas in water at 25°C its partial pressure over the solution is 760 torr.
UNIT—V
9. (a) What are computer hardware and software?
(b) Define the terms, algorithm and programming language.
(c) Find the decimal equivalents of the following binaiy numbers: 1+1=2
(i) (10010101)2
(ii) (11011.101)2
10. (a) Draw the block diagram of a computer and briefly describe the function of each unit. 1+4=5
(b) Convert the following decimal numbers tobinary: 1+1=2
(i) (0.6875)10
(ii) (21.6)10
550/1030 2016/SEM/EVEN/CHMH—203/292
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