Question

The rate of reaction is...

A. divided by stoichiometry coefficients.
B. can only be determined with the specific reaction stoichiometry.
C. multiplied by the stoichiometry coefficents.
D. constant for all reactants.

Answer 1

The rate of reaction is divided by the stoichiometry coefficients, because they balance out the rate at which substances react according to the balanced chemical equation. The rate is not universal for all reactants and is influenced by reaction conditions and stoichiometry. D. constant for all reactants.

Step-by-step explanation:

Understanding the Rate of Reaction

The rate of a chemical reaction is a measure of how fast the concentrations of reactants decrease or the concentrations of products increase over time. When considering the equation A → B, the rate of reaction can be expressed either as the decrease in concentration of reactant A or as the increase in the concentration of product B. These rates are inversely related to the stoichiometric coefficients of the balanced chemical equation.

The correct answer to the question 'The rate of reaction is...' would be A. divided by stoichiometry coefficients. This is because when we write a rate law, the rate of reaction for each substance is adjusted for its coefficient in the balanced chemical equation. In other words, the rate at which a substance reacts is taken relative to how much of it is specified by the equation stoichiometry. For example, if reactant A has a coefficient of 2, the rate of disappearance of A is half the overall reaction rate because two moles of A are required for every single occurrence of the reaction.

It's also important to understand that the rate of reaction is not constant for all reactants as it can change under different conditions such as temperature, pressure, and presence of catalysts. Moreover, to determine the specific reaction rate, one must also consider the stoichiometry of the reaction, as it can affect how different reactants and products interconvert.

Finally, the rate law often includes a specific rate constant that provides the relationship between the concentration terms and the rate of reaction. The units of this rate constant can vary depending on the overall order of the reaction.

Answer 2

The rate of reaction is divided by the stoichiometry coefficients to relate the change in concentration of one substance to another in the reaction. The correct answer to the student's question is A. Divided by stoichiometry coefficients.

Step-by-step explanation:

The rate of reaction is closely related to the stoichiometry of the reaction, which is the quantitative relationship between reactants and products in a chemical equation. When calculating the rate of a reaction, we must refer to the stoichiometric coefficients of the reactants or products involved. These coefficients reflect the proportion in which the substances react or are produced.

For example, if we have a reaction where A is converted to B, as represented by the equation A → B, the rate at which A disappears (which is negative since A is being consumed) can be divided by its stoichiometric coefficient to relate it to the rate of formation of B. Meanwhile, when dealing with the rate law of a reaction, we must be mindful of how the coefficients play into the rate expression, determining the order with respect to each reactant.

To address the student's question, the correct option is: A. Divided by stoichiometry coefficients. This means that when expressing the rate of reaction for a given reactant or product, you would divide by the stoichiometric coefficient associated with that species in the balanced equation.