During a chemistry experiment, the pressure of a gas, in kilopascals (kPa), was recorded at one-minute intervals. The scatterplot shows the recorded pressure , in kPa, of the gas minutes after the start of the experiment.
What was the average rate of change, in kPa per minute, of the recorded pressure of the gas from to ?
For an average-rate-of-change question based on a scatterplot, identify the two specified data points and use the slope formula: subtract the earlier -value from the later -value, then divide by the change in . Check that the units match the question, such as kPa per minute.
Hints
Locate the relevant points
Find the plotted points with -coordinates of and , and read their pressure values.
Use the slope relationship
Average rate of change is the change in the pressure divided by the change in time.
Set up the calculation
Subtract the pressure at minutes from the pressure at minutes, then divide that result by .
Desmos Guide
Enter the rate expression
In a blank Desmos expression line, enter .
Interpret the result
Desmos evaluates the expression as the change in pressure divided by the change in time, which is the average rate of change in kPa per minute.
Step-by-step Explanation
Read the two plotted points
The graph shows a pressure of kPa at minutes and a pressure of kPa at minutes. Thus, the relevant points are and .
Find the changes in pressure and time
The pressure change is kPa, and the time change is minutes.
Calculate the average rate of change
Divide the change in pressure by the change in time:
Therefore, the average rate of change is kPa per minute.