# Chemistry Experiment

Topics: Density, Water, Liquid Pages: 4 (1212 words) Published: December 4, 2012
General Chemistry I CHEM XXI Project Report Worksheet (4 pages max.)

Experiment title: How Do We Identify an Unknown Substance?
Guiding questions: State the question or questions that that you were trying to answer in this lab. How do you determine the two unknown types of plastic? What are the two unknown plastics?

Safety considerations: Briefly describe the safety measures you had to take to perform the experiments.

Before entering the lab, I put on my lab coat and practiced using my goggles in case of any spills or splashes. I also used proper methods for dispensing my mix liquids. /2p
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Procedures: Briefly describe the experimental procedures you followed to answer the guiding questions. Outline the specific problems you were trying to solve and how you did it.

1. /2 p
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Find the volume of the four known substances using a vernier caliper to make measurements. (For rectangular prism measure length, width, and height; For cylinder measure diameter, divide by half to find radius, and height) 2. Find the mass of each known substance using the electric balance. Make sure the balance is clean and calibrated to zeros. 3. Graph the volume and mass on an excel sheet to help determine the density of each plastic. The y-axis is the dependent and the x-axis is the independent, which in this case the y-axis is the mass and the x-axis is the volume. In the graph, add a linear trendline. Determine the slope to find the average density. 4. Once you have found the density for each known plastic, you will find the density of the two unknown plastics. First, use 50mL of water and place each plastic in the water and determine if they float or sink. Make sure to take note if they float or sink. 5. If the plastic floated, you will place it in a mixture of ethanol and water using the following steps(this is creating a mixture with a density between 0.920 g/mL and 0.953 g/mL): a. Place 40mL of...