To calculate the rate of a reaction at a specific time, what method should be used on a graph?

The method for calculating the rate of a reaction at a specific time using a graph involves measuring the gradient of a tangent at that particular point. This is because the rate of reaction is defined as how fast the concentration of reactants is changing over time, and graphically, this change is represented by the slope or gradient of the curve.

When you draw a tangent line to the curve at the desired time, the slope of this line gives you the instantaneous rate of reaction at that specific moment. The steeper the gradient, the faster the reaction is occurring at that time. This method allows for precise measurement at any point on the curve, making it more accurate than calculating an average over the entire reaction.

Other methods, like finding the area under the curve or measuring the height of the graph, do not provide information about the instantaneous rate at a specific moment, and averaging rates over the whole reaction could obscure important details about how the rate changes over time. Therefore, the gradient of the tangent is the most suitable approach for determining the reaction rate at a particular instant on a graph.