Question

Which one of the following sets of units is appropriate for a second-order rate constant?

A. s-1
B. mol L-1 s-1
C. L mol-1 s-1
D. mol2 L-2 s-1
E. L2 mol-2 s-1

Answer 1

Answer:

C. L mol-1 s-1.

Explanation:

Hello,

In this case, a rate law has the following general form:

$r=kC^x_i$

Whereas r accounts for the rate measured in M/s units, k is the rate constant whose units depends on the order of the reaction, C the concentration of the species in M units, contributing to the rate and x the order of the reaction.

In such a way, since in this case x equals two (second-order rate), the units of k turns out:

$\frac{M}{s}=\frac{mol}{L*s}=k*(\frac{mol}{L}) ^2\\\frac{mol}{L*s}=k*\frac{mol^2}{L^2}\\\\k=\frac{L^2*mol}{mol^2*L*s} \\\\k=\frac{L}{mol*s}$

Which matches with C. L mol-1 s-1.

Best regards.

Answer 2

The units for a second-order rate constant is:

C. $L*mol^{-1} s^{-1}$

Second order Rate Law:

Second order reactions can be defined as chemical reactions wherein the sum of the exponents in the corresponding rate law of the chemical reaction is equal to two. The rate of such a reaction can be written either as r = k[A]₂, or as r = k[A][B].

The units for second order reaction is $L*mol^{-1} s^{-1}$.

Thus, correct option is C.

Find more information about Second order reaction here:

brainly.com/question/8139015