Final answer:
To find the average rate of disappearance of A over an interval, subtract the initial concentration from the final concentration and divide by the time elapsed. The instantaneous rate at a specific time is the slope of the tangent line to the concentration-time graph at that point, and its units are M/s.
Step-by-step explanation:
The average rate of disappearance of A can be calculated by taking the difference in concentration of A at the beginning and end of a time interval and dividing it by the time duration. For instance, if the concentration of A at 0.0 s is [A]1 and at 10.0 s is [A]2, the average rate of disappearance between 0.0 s and 10.0 s is calculated as ([A]1 - [A]2) / (10.0 s - 0.0 s).
To find the instantaneous rate of disappearance of A at 15.0 s, you would look at the slope of the tangent line at 15.0 s on a graph that plots time versus [A]. The units for these rates would typically be molarity per second (M/s).The process for determining the instantaneous rate is analogous to finding the derivative in calculus since it involves the slope of a tangent line to the curve at a specific point. To determine the average rate of change of a function, you need to find the difference in the function's values at the starting and ending points, and then divide by the difference in the corresponding input values.
For example, to find the average rate of disappearance of A between 0.0 s and 10.0 s, you would subtract the initial concentration of A at 0.0 s from the final concentration of A at 10.0 s, and then divide by 10.0 s.
Similarly, to find the average rate of disappearance of A between 10.0 s and 20.0 s, you would subtract the initial concentration of A at 10.0 s from the final concentration of A at 20.0 s, and then divide by 10.0 s.