Question

First-Order Reactions (35) Azomethane decomposes into nitrogen and ethane at high temperatures according to the following equation: (CH3)2N2(g) — N2(g) + C2H6(g) The following data are obtained in an experiment: Time (h) [(CH3)2N2] 1.00 0.905 2.00 0.741 3.00 0.607 4.00 0.497 (a) By plotting the data, show that the reaction is first-order. (b) From the graph, determine k. (c) Using k, find the time in hours) that it takes decrease the concentration to 0.100 M. (d) Calculate the rate of the reaction when [(CH3)2 = 0.415 M.

first order reaction

Answer 1

Time (h) lin [(CH3)2N2] | [(CH3)2N2] -0.099820335 0.905 -0.299754654 0.741 -0.499226488 0.607 -0.699165253 0.497 In [(CH3)2N2] vs Time y = -0.1998x + 0.0999 R2 = 1 [zNz(εHɔ)] u 1 1.5 2 3.5 4 4.5 2.5 3 Time (h)

(a) plot of the f(CH3) Ng , us TIME IS STRAIGHT LINE SO Remeron IS FIRST ORDER. FOR A 1ST ORDER REACTION, lu (A) = ln (A) - kt (4), : initial CONCENTR MON, K is RMTE CONSTANT EQN OF plot of TRENDLINE IS : = -0.1998 nt 0.0999 lu (A) ust is STRAIGHT LINE WITH slope ==k A slopt = - 0.1998 = -k. RATE CONSTANT, Ik = 0, 19986') KA c) i (Cus), ve] - lu (C13), "s),- kt eu (0.100) = ln (0.905) - 0, 1998 htxt alt=llon IT CONCENTRATION TO DE CREUSE. TO 0.10019 TAKES .ll.on.For a) HE R = k [(CH3), M2) = 0.1998 5" x 0.41579 = 10:0829 19/h | RAME OF REACTION.