Question

Express the instantaneous rate of the following reaction in terms of all reactants and products.

\[\ce{2A + B -> 3C + 4D}\]

Answer 1

To express the instantaneous rate of the reaction

\[\ce{2A + B -> 3C + 4D}\]

In terms of all reactants and products, we use the derivative of concentration with respect to time for each species, divided by its stoichiometric coefficient.

Instantaneous rate expression is

\[\ce{Rate = \frac{1}{2} * \frac{d [A]}{dt}}\]

= \[\ce{-\frac{d [B]}{dt}}\]

= \[\ce{\frac{1}{3} * \frac{d [C]}{dt}}\]

= \[\ce{\frac{1}{4} * \frac{d [D]}{dt}}\]

Negative signs for reactants (A and B) because their concentrations decrease over time. Positive signs for products (C and D) because their concentrations increase over time. This equation gives the instantaneous rate of the reaction in terms of all reactants and products.