NEET Chemistry Chemical Kinetics Questions Solved

BOARD

Nitrogen pentoxide decomposes according to equation :

2N2O5(g)NO2(g) + O2(g).

This first order reaction was allowed to proceed at 40C and the data below were collected :

                [N2O5] (M)                Time (min)

                  0.400                        0.00

                  0.289                        20.0

                  0.209                        40.0

                  0.151                        60.0

                  0.109                        80.0

(a) Calculate the rate constant. Include units with your answer.

(b) What will be the concentration of N2Oafter 100 minutes?

(c) Calculate the initial rate of reaction.

(a)    K = 2.303tlog [A][A]

 Substituting the values, we get

           K = 2.30320log [0.400][0.289]

   or      K = 2.30320log 1.3840

   or      K= 0.0163 min-1

(b)     K = 2.303tlog [A][A]

        0.0163 = 2.303100log [0.400][A]

    or            log 0.400[A]=0.0163×1002.303

     or            log 0.400[A]=7.0777

                [A] = 0.078 M

(c) Initial Rate, R = K[N2O]

                         = 0.0163 min-1 (0.400)

                         =0.00652 M min-1 

 

 

 

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