01.07 Accuracy and Precision: Virtual Lab—Measurement (Text Version)
Measurement
Measurement is an important skill used for data collection and data analysis. Careful attention to the accuracy and degree of uncertainty of each measuring device is necessary for proper data collection. Significant figures are used to record or report measurements accurately.
This laboratory activity will give you the opportunity to get more familiar with some of the basic measuring devices that are common in chemistry labs. You will use the measurements performed in this lab to calculate density.
Part I: Density of an Unknown Liquid
Trial 1:
- Measure the mass of an empty graduated cylinder on the triple beam balance. The smallest marking on the balance are 0.1 g markings, or 10 markings between each one gram. The mass of the graduated cylinder is between the second and third mark after 25 grams. Record the mass of the graduated cylinder in your data table, being careful to use the correct number of significant figures.
- Measure the volume of liquid that has been added to the same graduated cylinder. The smallest markings on the graduated cylinder are 0.1 mL, or 10 markings between each one milliliter marking. The top of the liquid in the cylinder is between the fourth and fifth mark after eight mL. Record the volume of the liquid in your data table, being careful to use the correct number if significant figures.
- Now measure the mass of the graduated cylinder that now contains the liquid. The smallest marking on the balance are 0.1 g markings, or 10 markings between each one gram. The mass of the cylinder containing the liquid is between the first and second mark after 36 grams. Record the mass of the graduated cylinder with liquid in your data table, being careful to use the correct number of significant figures.
Once you have collected all of the measurements in your data table, you can complete the rest of the lab worksheet and submit it to your instructor. Be careful to follow all of the sig fig rules in the data table and calculations.