Question

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

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

Answer 1

To express the average rate of the reaction

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

In terms of all reactants and products, we divide the change in concentration of each species by its stoichiometric coefficient and the time interval.

Average rate expression is given as

\[\ce{Rate_{avg} = \frac{1}{2} * \frac{\Delta [A]}{\Delta t}}\]

= \[\ce{-\frac{\Delta [B]}{\Delta t}}\]

= \[\ce{\frac{1}{2} * \frac{\Delta [C]}{\Delta t}}\]

= \[\ce{\frac{1}{4} * \frac{\Delta [D]}{\Delta t}}\]

Negative signs for reactants (A and B) because their concentrations decrease. Positive signs for products (C and D) because their concentrations increase. This gives a complete expression of the average rate in terms of all species involved.