What does measuring the gradient of a tangent on a graph represent?

Measuring the gradient of a tangent on a graph represents the rate of the reaction at that specific moment in time. In the context of a graph that tracks the progress of a reaction, the tangent line at any given point indicates how quickly the products are forming or the reactants are being used up at that specific time. This is because the gradient, or slope, of the tangent line reflects the change in concentration of reactants or products over time.

As the reaction proceeds, the rate can change. Therefore, by determining the gradient of the tangent at a particular point, one can analyze the instantaneous rate of reaction rather than the average rate over the entire duration. This instantaneous rate is crucial for understanding how the reaction dynamics evolve, especially in reactions where the rate changes significantly during the course of the reaction.