Based on this plot, the reaction is __________ order in HI and the rate constant for the reaction is _______ M s-1.

Question

In a study of the decomposition of hydrogen iodide on a gold surface at 150 °C

HI(g)½ H₂(g) + ½ I₂(g)

the concentration of HI was followed as a function of time.

It was found that a graph of [HI] versus time in seconds gave a straight line with a slope of -1.57×10^-4 M s^-1 and a y-intercept of 0.141 M.

Based on this plot, the reaction is __________ order in HI and the rate constant for the reaction is _______ M s^-1.

Answer 1

If a plot of [HI] vs time yields a straight line, this tells us the reaction is ZERO order with respect to HI.

The slope of the line (-1.57x10-4 Ms^-1) tells us the negative value of k. So k = 1.57x10^-4 Ms^-1