Question

13.20 The following gas-phase reaction was studied at 290°C by observing the change in pressure as a function of time in a constant-volume vessel: CICO,CC13(8) — 2COC12(8) Determine the order of the reaction and the rate con- stant based on the following data: Time (s) P (mmHg) 0 181 513 1164 15.76 18.88 22.79 27.08 where P is the total pressure.

Answer 1

consider the following reaction : Cleos cels (g) 2lock (g) The pressure e given is the total pressure. To find out the order of reaction, we need to know the partial pressure of cloacala ( Pelcoa Cols) once it is known to us We plot a graph as presure (P) vs Tore (T) and We check one by one as a trial basis. il we get a straight line ithen the respective order is known. Parameters In P Vs time Yp Us time P vs time Nature of graph straight line straight line straight line order of the reaction firth andon... second onder Tero order slope of the line will be equal The to magnitude of reate constanta by creating an ICE Santial pressure of table i we can Calculate the alcoacels as shown below: وطمعهم او ولكم في ج- (وولت معاه Initial pressure 15.76 Change -n Einal pressure 15.76 ox

from the ICE table in Total pressure (P) = (15146-2) +22 15.76 tn Change in pressure, n = p. 15.76 pressure of elco Cela (Peiceseci) = 15.76-2 Below are the calculations : - Timelt, seed) Total Pressive / Change in the pressure of cleocals In Pellosed 15176 15176 od : 464 181 18188 3:12 12.64 513 7:03 8.73 2:16 1164 27.08 2444 22.79 As it the plot means the Infricoacelo Vs (t) gives a straight line reaction is a frust andey Meantion from the quaph, the line equation isyan 0.001082 I do Q: 404 Thus, the slope of the line is Since the magnitude of slope be equal to hate constant, will be 1088 1035-1 0.00108 of the the late line will constant Therefore the rate constant is 16088103 st

InP Vs time y = -0.0011x + 2 7404 nomes InP 200 4 bə 1600, 1200 time (s) 1000 1200 1400