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Punjab university lahore
 












 

              

 

            B.Sc. Punjab University 2013

Chemistry (New Course)                                         Paper: A       
 Time Allowed: 3 Hrs.                                      Max. Marks: 50 Attempt any FIVE questions. All questions carry equal marks. 
Q:1 
a) Explain the following terms: 3+4+3 
 i- Collision number
 ii-Collision frequency
 iii- Collision diameter
b) -Give the experimental technique for the determination of 
     molecular velocities of gases. 
c)  Determine the temperature at which Crms of SO2 ? is same as 
     that of O2 at 27o C.
a)  What do you mean by magnetic permeability and magnetic 
     induction? 4+3+3 
b)  What is dipole moment? Give refraction method for the 
     determination of dipole moment. 
c)  The refractive index of benzene at 25°C for light of wavelength 
     600 nm is 1.498. The density of benzene is 0.874x10'’ kgm'' 
     Calculate the molar polarization (Pm) and polarizability (œ) of 
     benzene. 
Q:3 
a)  Derive principle quantum number (n) from Schrodinger wave 
     equation. 5+2.5+2.5 
b)  What is the normalization of the wave equation? 
c) The kinetic energy associated with moving electron is 4.55 x 10 
    ^-28 J. Calculate its wavelength; me = 9.1 x 10^-31 kg; h = 6.62 x 
     10^-34 Js.
 a) What do you mean by Gibb’s Free energy and Helmholtz Free    
    energy? How do you compare these two types of Free 
      energies? 5+2+3 
b)  Derive Boltzman Planck equation. c) The vapour pressure of 
     a liquid at 85°C and 96°C are 560 to it and 650 torr respectively.
     Calculate ∆Hv of a liquid at this temperature range   
     (R=8.314JK-1M-1 
Q:5 
a)   Discuss the kinetics of first order 
      reaction. Derive the expression for half-life of first order 
      reaction.   5+3+2 
b)  Explain transition state theory. c) The rate of a particular reaction 
      becomes four times when temperature changes from 20°C to 
      40°C. Calculate energy of activation of this reaction. 
Q:6
a) Derive Kp = Kc(RT) ∆n. 3+4+3 
b) Discuss the quantitative effect of temperature on equilibrium 
    constant. 
c) How do you discuss the relationship between degree of dissociat 
     ion and the Kp value of the following reaction N2 O4 ↔ 2NO2
Q:7 
a) Explain the Vont Haff s factor “i”. How it can be explained from 
     the dissociation and association of a substance in the solution 
      state. 4+3+3 
b) What are Colloids? Give some of its uses. 
c) A substance “A” of molar mass 98 associates as 2A→A2. When it 
    is dissolved in. CCl4 if l0g of A is dissolved in 2 kg of CCl4 the 
     freezing point is lowered by 1.08°C. Kf for CClis 3.18K. 
     Calculate degree of dissociation of A. 
Q:8 
a)  W'hat is Freundlich adsorption Isotherm? Discuss its 
     graphical representation. 4+3+3
b) Whal is powder method for the crystal structure determination 
      by x-rays? 
c)  A crystal has interplaner distance of 2.04 A° and wavelength 
     of x-rays used is 1.54 x 10'[1]m. Calculate the angle of 
     deflection.                                                                                 
Q:9 a)  Discuss the equation which gives relationship between 
          electrical energy and chemical energy. 4+3+3 
b) What is Nerst equation? How it is applied to determine the EMF 
     of celt? 
c) Explain equivalent and molar conductance and how they are 
     measured?                                                                                
Q: 10 Write notes on any two of the following: (5+5)
i)   Bragg equation for the diffraction of the x-rays. 
ii)  Calomel electrode. Evaluation of energy of activation from 
       two temperatures. --------------------------------------------------------------------------------

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