Question

QUESTION 4 Ammonia decomposes at very high temperature according to the following overall reaction: NH3(g) -> NH2(g) + H(g) A chemist has performed this reaction and measured the ammonia concentration versus reaction time. She then plotted the data in three different ways: y = -0.3784x + 78.54 Y = -0.0059x +4.3707 y = 9E-05x +0.0125 Based on these plots, what is the reaction order with respect to NH3? Zero order First order

Answer 1

Only the plot of 1/[NH3] vs t has all the data points lying on the best fit line, that is there is linear relationship between 1/[NH3] and t. This happens only in case of second order reactions having integrated rate law of 1/[A] = 1/[A]₀ + kt.

The zero order reaction has [A] vs t a straight line plot and first order equation has ln[A]₀ vs t a straight line plot.

Thus reaction order is second order.