Question

Express the instantaneous rate of the reaction, \[\ce{A + 3B -> 2C + 4D}\], in terms of all reactants and products.

Answer 1

For the reaction

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

The instantaneous rate of reaction is expressed in terms of the rate of change of concentration of each reactant and product, adjusted for their stoichiometric coefficients

\[\ce{Rate = -\frac{d[A]}{dt}}\]

= \[\ce{-\frac{1}{3} \frac{d[B]}{dt}}\]

= \[\ce{\frac{1}{2} \frac{d[C]}{dt}}\]

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

Negative signs (−) for A and B indicate their concentrations decrease with time (reactants). Positive signs for C and D indicate their concentrations increase with time (products). Each term is divided by its stoichiometric coefficient to ensure all expressions represent the same reaction rate.