Question

Choose the expressions that properly express the rate of the following reaction in terms of disappearance of reactants and appearance of products. Reaction in picture below

Answer 1

In a given reaction, the rate of the reaction is given by the change in concentration of chemical species in a given amount of time multiplied by the inverse of the stoichiometric coefficient.

E.g. reaction: \(\sf a~A+ b~B\rightarrow c~C\)

where lowercase letters are stoichiometric coefficients and uppercase are the chemical species,

rate of reaction\(\sf =-\dfrac{1}{a}\dfrac{\Delta[A]}{\Delta t}=-\dfrac{1}{b}\dfrac{\Delta [B]}{\Delta t}=+\dfrac{1}{c}\dfrac{\Delta [C]}{\Delta t}\)

note that the rates of the reactants are negative because they are being used up, while the rates of the products are positive because it's being made.