CHEM 107- General Chemistry Lab I

Balances, Pipets, and Data Analysis Pre-Lab Assignment:

Before coming to lab, you should:

1. Print the handout labeled “Balances, Pipets, and Data Analysis” from the Chem 107 web page. Be sure to bring the handout and data pages with you to lab. You will turn in the data pages at the end of the lab period. The procedure you will follow in lab will come from this handout. The reading assignment in the lab manual and text will be used for background information. Be sure to read the handout, including the background reading assignment, so that you understand all procedures and calculations.
2. Don’t forget to bring your safety goggles to lab. Laboratory work is not allowed without proper eye protection.
3. Complete the following on a separate sheet of paper. This pre-lab assignment is due to your instructor at the beginning of lab, and before lab work can begin.

1. In this lab, you will determine the density of water. It is a quantitative experiment and thus accuracy is essential. What is the difference between using a graduated cylinder, a volumetric pipet and a graduated pipet for measuring volumes? What is the best piece of glassware to use to quantitatively measure a known volume of a liquid? (4 pt)

2. In this lab, you will be required to prepare a graph of mass vs. volume using an Excel spreadsheet from the data you collect in lab. On what axis will mass be plotted? On what axis will volume be plotted? How will you use your graph to determine the density of water? (4 pts)

3. A student needs 118.0 g of ethanol for an experiment, but only has a graduated cylinder available. If the density of the alcohol is 0.789 g/mL, how many milliliters of ethanol would be needed to get the correct mass? Show your work, reporting your answer to the correct number of significant figures, and with the correct units. (2 pt)