Question

Determine the units of the rate constant for all four reactions listed in the problem above, and enter the correct choices from the list below. Enter 4 letters in order (e.g. ABCD or CBED)a. mole L-1 sec-1
b. mole-1 L sec-1
c. mole2 L-2 sec-1
d. mole-2 L2 sec-1
e. None of the above.

Answer 1

The given question is incomplete. The complete question is :

For the net reaction: $2AB+2C\rightarrow A_2+2BC$, the following slow first steps have been proposed.

A. $2C+AB\rightarrow AC+BC$

B. $2AB\rightarrow A_2+2B$

C. $C+AB\rightarrow BC+A$

D. $AB \rightarrow A + B$

Determine the units of the rate constant for all four reactions listed in the problem above, and enter the correct choices from the list below. Enter 4 letters in order (e.g. ABCD or CBED)

a. $moleL^{-1 }sec^{-1}$

b. $mole^{-1}Lsec^{-1}$

c. $mole^2L^{-2}sec^{-1}$

d. $mole^{-2}L^2sec^{-1}$

e. None of the above.

Answer:  A. $2C+AB\rightarrow AC+BC$ : $mol^{-2}L^2s^{-1}$

B. $2AB\rightarrow A_2+2B$ : $k=mol^{-1}Ls^{-1}$

C. $C+AB\rightarrow BC+A$ : $k=mol^{-1}Ls^{-1}$

D. $AB \rightarrow A + B$:  $k=s^{-1}$

Explanation:

Rate law says that rate of a reaction is directly proportional to the concentration of the reactants each raised to a stoichiometric coefficient determined experimentally called as order.

1. $2C+AB\rightarrow AC+BC$

$Rate=k[C]^2[AB}^1$

$molL^{-1}s^{-1}=k[molL^{-1}]^2[molL^{-1}}^1$

$k=mol^{-2}L^2s^{-1}$

2. $2AB\rightarrow A_2+2B$

$Rate=k[AB]^2$

$molL^{-1}s^{-1}=k[molL^{-1}]^2$

$k=mol^{-1}Ls^{-1}$

3. $C+AB\rightarrow BC+A$

$Rate=k[C}^1[AB]^1$

$molL^{-1}s^{-1}=k[molL^{-1}]^1[molL^{-1}]^1$

$k=mol^{-1}Ls^{-1}$

4. $AB \rightarrow A + B$

$Rate=k[AB]^1$

$molL^{-1}s^{-1}=k[molL^{-1}]^1$

$k=s^{-1}$