7 Experiment 2: Introduction, Objectives, and Pre-Laboratory Work

Introduction: Chemistry heavily involves using accurate and precise measurements and recording observations during an experiment. As such, this activity introduces students to how to use various laboratory measuring devices and how to correctly record measurements using correct significant figures (aka sig figs) and apply various statistics to data.

Objectives:
Upon successfully completing this activity, student should be able to:
1. Record measurements using laboratory glassware with both correct sig figs and units.
2. Apply mathematical statistics to express answers with correct sig figs and units.
3. Demonstrate how to properly use laboratory glassware and equipment.
4. Determine the mean, range, and standard deviation for data sets.
5. Distinguish the difference between precision and accuracy.
6. Critically evaluate experimental results.

Pre-Lab Assignments:

1. Carefully read the protocol for Experiment 2.
2. Watch the required videos:
   University of New Hampshire: The Metric System (4:49)
   Measuring Volume Using a Graduated Cylinder (2:16)
   Using an Electronic Balance (1:34)
   Accuracy and Precision  (2:17)
   How to calculate standard deviation (7:13)
3. Complete your Pre-laboratory Work (Objective, Safety Statement, Procedure Summary, and Answers to the Pre-Laboratory Questions) by 11:59 pm on Sunday, January 29, 2023.
4. Submit your Pre-laboratory Work to Canvas as a single document to Canvas.
   CamScanner and Dropbox are free apps that can be used to upload a series of photos as a single pdf. The notes app on an iPhone can also save a series of photos as a single pdf.

Pre-Lab Questions

Answer each prompt clearly and thoroughly. Correct grammar, spelling, capitalization, and punctuation are necessary for full credit. You are expected to answer these questions by using your lab manual and lecture notes.  If you use an online source to answer any of these questions, cite your source by listing the url for the website to avoid receiving a grade of 0 for plagiarism.

1. Define significant figures (aka sig figs).
2. Where is the uncertain digit located in a recorded measurement?
3. Identify how many significant figures in the recorded measurement of 4.70 cm. Identify the certain digits(s) and the uncertain digit(s).
4. What physical property is measured by the unit cm?
5. What physical property is measured by the unit gram?
6. What physical property is measured by the unit mL?
7. What physical property is measure by the unit °C?
8. Explain how a mean is calculated.
9. Explain how the range of a data set is calculated.
10. What is the equation for standard deviation?