What is the Difference Between Instantaneous Rate and Average Rate?

The main difference between instantaneous rate and average rate lies in the time frame and the basis of measurement. Here are the key differences between the two:

• Instantaneous Rate:

1. Refers to the rate of a reaction at a particular moment or for a very short time period.
2. It occurs within a short span of time.
3. Instantaneous rate can be determined by finding the slope of the tangent to the concentration vs time curve at a specific time.

• Average Rate:

1. Refers to the rate of change of concentration of substances for a definite interval of time.
2. It occurs during a larger span of time.
3. Average rate is calculated using the formula: $$Average\,Rate = \frac{-ΔA}{Δt} = \frac{A2 - A1}{T2 - T1}$$ where ΔA is the change in concentration, Δt is the time interval, and A1 and A2 are the initial and final concentrations, respectively.

In summary, instantaneous rate measures the rate of a reaction at a specific point in time, while average rate measures the rate of a reaction over a longer time period. Instantaneous rate is determined by finding the slope of the tangent to the concentration vs time curve, whereas average rate is calculated using the formula mentioned above.

Comparative Table: Instantaneous Rate vs Average Rate

The following table compares the differences between instantaneous rate and average rate:

While both rates are used to find the slope, the average rate calculates the slope of the secant line, and the instantaneous rate calculates the slope of the tangent line. In linear graphs, the average and instantaneous rates will be the same at any point, but in curved graphs, they will be different.