Friday, June 12, 2009

103 CHEMISTRY

BTECH DEGREE I&II SEMESTER EXAMINATION MAY 2007
ENGINEERING CHEMISTRY
Time:3 Hrs Max marks:100
.1) What are liquid crystals? Give its major applications.
2) Explain Frenkel defect & Schottky defect.
3) How do you explain the acidic & basic nature of the following substances
(i) HCLaq (ii) BF3 (iii) NaOHaq (iv) NH3
4) What are fast reactions? Give 2 eg & mention 3 methods to study fast reactions.
5) Derive Kirchoff’s equation.
6) What is free energy? How is it related to equilibrium constant?
7) Explain addition & condensation polymerization
8) What is an optical fibre? What are its advantage & applications?
Part B
2. a) Draw & label Born Haber Cycle for Kcl.
b) Calculate the lattice energy of KCL using the given data.
Enthalpy of formation = -438 KJ/mol
Enthalpy of sublimation = 89KJ/mol
Ionisation energy =425KJ/mol
Electron affinity =-355KJ/mol
Enthalpy of dissociation = 244KJ/mol
c) What is super conductivity? What are the applications of super conductors?
OR
3. a) How is band theory used to explain conductor ,insulator,& semi conductor?
b) What is Fermi level?
c) What are intrinsic & extrinsic semi conductors?
4. a) Define order of a reaction . Derive the rate expression for first order reaction.
b) Apply the rate expression to find out an equation for half life of a first order
reaction.
c) In a first order reaction it takes 40.5 minutes for the reactant to be 25% decomposed.
Calculate the rate constant of the reaction. I n what time it will be 50% complete?
OR
5. a) What is corrosion?
b) Write notes on oxidation corrosion, corrosion by evolution of hydrogen & galvanic
corrosion.
c) What is sacrificial anodic protection method?
6. a) Derive a Gibb’s Helmholtz equation.
b) What is Troutn’s rule?
c) Explain Nernst heat theorem.
OR
7. a) What is enthalpy or heat content?
b) Show that change in enthalpy H=E+PV
c) Give different forms of statement of second law of thermodynamics.
8. a) What are advantages of plastics?
b) Write short notes on thermo plastics.
c) Explain injection moulding.
OR
9. a) Give major properties of refractories.
b) What are the raw materials of Portland cement?
c) What are the applications of fullerene?
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