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Punjab university lahore |

### B.Sc. Punjab University 2013

Chemistry (New Course) Paper: ATime 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 CCl4 is 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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