Chapter 1, Problem 22RPS

### Chemistry & Chemical Reactivity

10th Edition
John C. Kotz + 3 others
ISBN: 9781337399074

Chapter
Section

### Chemistry & Chemical Reactivity

10th Edition
John C. Kotz + 3 others
ISBN: 9781337399074
Textbook Problem

# The accepted value of the melting point of pureaspirin is 135 °C. Trying to verify that value, you obtain 134 °C, 136°C133 °C, and 138 °C infour separate trials. Your partner finds 138 °C,137 °C, 138 °C, and 138 °C. (a) Calculate the average value and percent error for your data and your partner's data. (b) Which of you is more precise? More accurate?

(a)

Interpretation Introduction

Interpretation: The average and percent error in each case has to be calculated.

Concept introduction:

Precision: Is a measurement indicates how well several determination of the same quantity agree.

Accuracy: Is the agreement of a measurement with the accepted value of the quantity.

Percent error: The difference between measured result and the accepted value.

Percenterror=ErrorinmeasurementAcceptedvalue×100%

Error in measurement = Experimentally determined value - Accepted value.

Explanation

The average density and percent error is calculated as,

Average density Value for Method A and B:

AverageÂ densityÂ forÂ MethodÂ 1:Â 134+Â 136Â +Â 133Â +Â 1384Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â =Â 135.25âˆ˜C.AverageÂ densityÂ forÂ MethodÂ 2:Â 138+Â 137Â +Â 138Â +Â 1384Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â =Â 137.75âˆ˜C

Hence, the average for method 1 and 2 are obtained as shown above.

Percent error for Method A and B:

Errorâ€‰inâ€‰measurementÂ =â€‰135.25âˆ˜CÂ -Â 135âˆ˜CPercentâ€‰errorâ€‰forâ€‰methodâ€‰1â€‰=â€‰â€‰135

(b)

Interpretation Introduction

Interpretation: The method that is more precise and accurate has to be given.

Concept introduction:

Precision: Is a measurement indicates how well several determination of the same quantity agree.

Accuracy: Is the agreement of a measurement with the accepted value of the quantity.

Percent error: The difference between measured result and the accepted value.

Percenterror=ErrorinmeasurementAcceptedvalue×100%

Error in measurement = Experimentally determined value - Accepted value.

### Still sussing out bartleby?

Check out a sample textbook solution.

See a sample solution

#### The Solution to Your Study Problems

Bartleby provides explanations to thousands of textbook problems written by our experts, many with advanced degrees!

Get Started