Molecular Structure Lab Report: Determining Polarity Instructions: For this investigative phenomenon, you will investigate why certain substances, such as oil and vinegar, don't mix. To do so, you will combine various compounds, compare their solubility, and determine their polarity. Fill in each section of this lab report and submit it to your instructor for grading.

Title:
Objective(s):
Hypothesis: Create a hypothesis that predicts the polarity of iodine solution, vinegar, vegetable oil, salt, water, and rubbing alcohol. Procedures: This lab already includes materials and a summary of steps to follow. List and explain your controlled variables, independent variable, and dependent variable for this lab.
Materials • deionized (distilled) water • rubbing alcohol • vegetable oil • iodine solution • sodium chloride (salt) • acetic acid (vinegar) • test tubes or clear plastic cups • tablespoon and teaspoon • stirring sticks • permanent marker for labeling

Safety • Always wear eye protection and use gloves when handling chemicals in a laboratory area. • Students should wash their hands thoroughly before leaving the laboratory area. • Dispose of any chemicals by washing used test tubes with soap and water or washing used cups then throwing them away in a trash bin.

Variables: Remember, controlled variables are factors that remain the same throughout the experiment. An independent (test) variable changes so that the experimenter can see the effect on other variables. The dependent (outcome) variable will change in response to the test variable. Controlled variables: Independent Variable: Dependent Variable:

Summary of Steps:
1. Using the steps for predicting the polarity of compounds, determine the polarity of water (H2O). Place your answers in table one. Once you have successfully predicted the polarity of water, you will be able to determine the polarity of the other compounds using steps two through five of the experiment.
2. Put about 2 tablespoons of deionized water into each of two labeled test tubes or clear cups. Add about 2 tablespoons of vinegar to one cup and 2 tablespoons of iodine solution to the other. Mix the contents with a stirring stick. In table two, indicate whether the solutes (vinegar and iodine solution) are soluble in the solvent (water). Then conclude whether the compound is polar, nonpolar, or ionic. (Hint: Like substances dissolve like substances, and polar solvents dissolve ionic compounds.)

3. Put about 2 tablespoons of vegetable oil into each of two labeled test tubes or clear cups. Add about 2 tablespoons of rubbing alcohol to one cup and 1 teaspoon of salt to the other. Mix the contents with a stirring stick. In table two, indicate whether the solutes (rubbing alcohol and salt) are soluble in the solvent (vegetable oil). Then conclude whether the compound is polar, nonpolar, or ionic.

4. Put about 2 tablespoons of rubbing alcohol into each of two labeled test tubes or clear cups. Add about 2 tablespoons of water to one cup and 2 tablespoons of vinegar to the other. Mix the contents with a stirring stick. In table two, indicate whether the solutes (water and vinegar) are soluble in the solvent (rubbing alcohol). Then conclude whether the compound is polar, nonpolar, or ionic.

5. Put about 2 tablespoons of vinegar into each of two labeled test tubes or clear cups. Add about 2 tablespoons of iodine solution to one cup and 2 tablespoons of vegetable oil to the other. Mix the contents with a stirring stick. In table two, indicate whether the solutes (iodine solution and vegetable oil) are soluble in the solvent (vinegar). Then conclude whether the compound is polar, nonpolar, or ionic.