CBSE AND AIPMT: CHEMICAL KINETICS COMPLETE TEST

TEST PAPER NO. 4 TOPIC : CHEMICAL KINETICS M.M. 50 TIME: 3 HRS. Name of Student________________________________ Roll No. _______________ Q.NO. 1-10 carries 1 mark, 11-20 2 marks, 21-25 carries 3 marks, 26 carries 5 marks. 1. In a reaction, 2A Products,the concentration of A decreases from 0.5 molL-1 To 0.4 mol L-1 in 10 minutes. Calculate the rate during this interval? 2. For a reaction, A+B Product, the rate law is given by, r=k[A]1/2[B]2 what is the order of reaction? 3. What will be the effect of temperatue on rate constant? 4. What is meant by pseudo first order reaction? 5. What is meant by order of reaction? 6. Derrive the steps of reaction for a reaction: 2N2O5 4NO2 + O2 Rate = k [N2O5]1 7. What is meant by molecularity of reaction? 8. By what factor a reaction with reaction coefficient 2 increases when the temperature is increased from 300 K to 400 K? 9. What is the effect of catalyst on rate of reaction? 10. The decomposition of NH3 on platinum surfae is zero order reaction. What are the rates of production of N2 and H2 if k =2.5 x 10-4 mol L-1? 11. What are the different factor which affect the rate of reaction? 12. A reaction is second order with respect to a reactant. How is the rate of reaction affected if the concentration of the reactant is: a. Doubled b. Reduced to half 13. The rate constant for a first order reaction is 60 s-1 How much time will it take to reduce the initial concentration fo the reactant to its 1/16 th value? 14. For a first order reaction, show that time required for 99% completion is twice the time required for the completion of 90% of reaction. 15 A first order reaction takes 40 min. for 30% decomposition. Calculate t1/2 16 The decomposition of hydrocarbon follows the equation K=(4.5x1011s-1)e-28000K/T Calculate Ea. 17. The decompostion of A into product has value of k as 4.5 x 103 s-1 at 10oC and energy of activation 60 kj mol-1 At what temperature would k be 1.5 x 10 4 s-1 18. The time required for 10 % completion of a first order reaction at 298 K is equal to that required for its 25% completion at 308 K. If the value of A is 4 x 1010 s-1. Calculate k at 318 K and Ea. 19. The rate of a reaction quadruples when the temperature changes from 293K to 313 K. Calculate the energy of activation of the reaction assuming that it does not change with temperature. 20. Sucrose decomposes in acid solution into glucose and fructose according to the first order rate law, with t1/2 = 3.00 Hrs. What fraction of a sample of sucrose remains after 8 hours? 21. A reaction is first order in A and second order in B: i. Write the differential rate equation ii. How is the rate affected on increasing the concentration of B three times? iii.How is the rate affected when the concentrations of both A and B are doubled? 22. The rate constants of a reaction at 500 K and 700 K are 0.02 s-1 and 0.07 s-1 respectively. Calculate the values of Ea and A. 23. The first order rate constant for the decomposition of ethyl iodide by the reaction: C2H5I(g) C2H4(g) + HI(g) at 600 K is 1.60 x 10-5 s-1 Its energy of activatin is 209 Kj/mol. Calculate the rate constant of the reaction at 700 K. 24 Prove: 10 t1/2 = t99.9 25 During nuclear explosion, one of the products is 90Sr with half-life of 28.1 years. If 1 gm of 90Sr was absorbed in the bones of a newly born baby instead of calcium, how much of it will remain after 10 years and 60 years if it is not lost metabolically. 26 What is meant by Average rate and Instantaneous rate. Determine the Rate law and order of reaction for A and B from the given data: EXPERIMENT Conc. [A] mol/litre Conc. [B] mol/litre Rate of reaction mol/litre/sec I 0.1 0.2 2 X 103 II 0.2 0.2 4 X 103 III 0.1 0.4 8 X 103 Also determine value of rate constant. And find the rate if the conc. Of [A] = 0.7 mol and [B] = 0.3 mol.