How is reaction rate typically measured?

Reaction rate is typically measured as the change in concentration of a reactant or product over time because chemical reactions involve the transformation of reactants into products, which directly affects their concentrations. As a reaction progresses, the concentration of reactants decreases while the concentration of products increases. By observing how these concentrations change over a specific time frame, we can quantify the rate of the reaction.

This method allows for a clear and direct way to treat the dynamics of reactions, making it possible to derive rate laws and understand the kinetics involved. For example, if the concentration of a reactant decreases from 0.5 M to 0.3 M over a 2-second interval, this information can be used to calculate the reaction rate for that time frame.

In comparison, measurement based on pressure, temperature, or volume may not provide a straightforward relationship to the rate of the reaction for all types of reactions. Therefore, focusing on concentration changes is the most common and effective approach for measuring reaction rates.