Question

clicker question
for the hypothetical chemical reaction a + b → c a
plot of a versus time was found to give a straight line
with a negative slope. what is the order of the
reaction with respect to a?
a. zeroth
b. first
c. second
d. third
e. not possible to determine the order from this
information
36
select an answer

Explanation:

• For a zeroth - order reaction, the integrated rate law is \([A]=[A]_0 - kt\), which is in the form of \(y = mx + b\) (\(y=[A]\), \(x = t\), \(m=-k\), \(b = [A]_0\)). So, a plot of \([A]\) versus \(t\) gives a straight line with a negative slope for a zeroth - order reaction.
• For a first - order reaction, the integrated rate law is \(\ln[A]=\ln[A]_0-kt\), so a plot of \(\ln[A]\) versus \(t\) gives a straight line.
• For a second - order reaction, the integrated rate law is \(\frac{1}{[A]}=\frac{1}{[A]_0}+kt\), so a plot of \(\frac{1}{[A]}\) versus \(t\) gives a straight line.

Answer:

A. zeroth