Question

en pentaxide NOx decomposes as shown below: 2 N2O () - 4 NO2(g) + O2 () he reaction is first onder and of the concentration of experimental 55 C is shown below. What are (1) the half-c. reaction at 55 C e concentration of N205 as a function time for an the half-life; and (ii) the rate constant for IN 205] vs time 0.020 0.015 ERASER Peniel POLYME IsoN 0.005 0 100 200 300 400 500 600 700 time/s

Answer 1

According to the graph the value can be tabulated as following

[N2O5]	0.020	0.017	0.014	0.012	0.010	0.008	0.007	0.006
time/s	0	100	200	300	400	500	600	700

Equation for the first order rate constant is given by

co (Initial concentration) k (rate constant) = f(time) in c(Final concentration)

= 1 Co-C700 t°C -6700 In

Where, c_o= 0.020 and c₇₀₀ = 0.006

Let's calculate the value for rate constant at t=200 s

c_t=0.014

1.0.020 -0.006 “ 200 0.014 - oons = 0.0027s-1

Let's calculate the value for rate constant at t=300 s

c_t=0.012

1 0.020 - 0.006 3000.012 -0.006 = 0.0027 s-1

Values of rate constant indicates the reaction is first order.

Let’s say rate constant (k) of the reaction is

  

k = 0.0027 s-1 = 2.7 X 10-35-1

Then half life of the reaction will be

0.693 k 0.693 .7 x 10-35-1 = 256.6 s 4/ 2 2