Chemical Kinetics and Photochemistry — DU B.Sc (hons) Chemistry Previous Year Question Papers

3. a. Explain Vant Hoff differential rate equation method used for the determination of order of b. The activation energy of a non-catalysed reaction at 37°C is 83.68 kJ mol and the activation energy of the same reaction catalyzed by an enzyme is 25.10 kJ mol ". Calculate the ratio of the rate constants of the enzyme-catalysed and the non-catalysed reaction. c. Define Frank Condon principle of electronic transition. Explain the reason of vertical transition in Jabolinski diagram of separation vs energy graphs. 5,5,5 4. a. What is the difference between rate constant and rate of reaction ? Give the units of rate constant for zero, first and second order reaction. b. From the following data for the decomposition of NO, in carbon tetrachloride solution at 48°C. show that the reaction is of the first order and calculate the rate constant. Time/ min 10 15 202 00 c. Calculate the number of photons given in 10 minutes by a 500 watt monochromatic source of 480 nm wavelength. 5,5,5 5. a. Why the reactions of third and higher orders are usually not very common? b. The half life of a first order chemical reaction A * B is 10 min. What percent of reactant remains after 40 min. c. i) What is Stark-Einstein law of photochemical equivalence? ii) Explain Photosensitisation with example. 5,5,5 6. a. Explain the effect of temperature on the rate of a chemical reaction? ). Define the term Activation energy. The activation energy of a reaction is 40 kJ mol' an he value of rate constant at 40 °C is 1.8 x10°s'. Calculate the frequency factor A c. Differentiate between Primary process and secondary process in photochemistry with