The Mixture Mystery

Title: The Mixture Mystery Goal: Students will learn how to separate mixtures by utilizing paper chromatography, solubility, and magnetism as well as manual methods of separation. Objective: Students will separate mixtures using chromatography, solubility, and magnetism. Materials: I Paper chromatography 1. filter papers 2. 500 mL beakers 3. Acetone 4. 4 or 5 different brand ink pens (use 1 as unknown) 5. stapler 6. pencils 7. rulers 8. Watchglasses II Sand/Salt/Iron Separation 1. Sand 2. Salt 3. Iron shavings 4. magnets 5. warm water 6. 100 mL beakers 7. beaker tongs 8. balance 9. hot plates III Bean counting 1. Beans (2 or 3 colors; need to be same general size) 2. Large glass bowl or large beaker (2 L or larger) 3. 50 mL beakers 4. 100 mL beakers State Standards: Math: NO.1.7.1 NO.3.7.6 M.13.7.2 Science: PS.5.7.5 PS.5.7.6 PS.5.7.7 PS.5.7.10 Lesson Procedure: 1. 2. 3. Talk with the students about common mixtures and compounds. Ask their ideas and opinions on separating the components of these mixtures and compounds. Introduce real world applications and the importance of separating mixtures. Give the students the handout and allow them time to read through it and answer any questions they may have about it. Student Procedure: (Write everything in complete sentences!!!) I. Statistics & Separation 1. 2. 3. Obtain a 100 mL and a 50 mL beaker. Locate the large jar of mixed beans. Using the 2 beakers that you have, come up with an experiment to determine the percent of white beans in the mixture without counting the whole jar! Construct a data table and record all of your data in the table. Determine the average percent of white beans in the mixture. (use at least 3 trials to get an average) 4. II. Separating a soil sample 1. Obtain a 7 – 10 gram soil sample. The sample is a mixture of sand, salt, and iron. Think about how this mixture could be separated and write down your ideas. Weigh your beaker and record the mass. Pour the mixture into a 100 mL beaker and record the mass again. (The mass of the soil sample can be determined by subtraction. This method is called weighing by difference) 2. (hint: think about each component of the mixture individually) 3. 4. 5. 6. Determine the mass of the mixture. Using the knowledge that you have about solubility and magnetism, separate the mixture and determine the percent of sand in the mixture. a. Use the magnet to stir your mixture and remove all of the iron shavings. b. Re-weigh your beaker to determine the mass of the iron. c. Use warm water to remove the salt from the mixture. Rinse the mixture at least 3 times to remove all of the salt. d. Using the hot plate, remove the extra water from the mixture by evaporating it. (be careful not to splatter the sand out of the beaker. Use a screen to cover it, and use beaker tongs to remove it from the hot plate) 7. 8. 9. Weigh the beaker with the sand and determine the mass of the sand in the mixture. Using this data, determine the percent of sand, iron, and salt that was in your original mixture. Record your observations and do all calculations it the area provided. Mass of Beaker Mass of Beaker with 3 component Mixture Mass of Beaker with Sand and Salt Mass of Beaker with Dried Sand __________________________________________ __________________________________________ __________________________________________ __________________________________________ DON’T FORGET TO PUT YOUR UNITS AND SHOW ALL WORK! % Sand in mixture % Salt in mixture % Iron in mixture :_______________ :_______________ :_______________ iii Identification by Colors 1. Obtain a piece of chromatography paper from the chromatography kit and cut a 6cm x 10cm piece to use in the ink analysis Draw a line 1.5 cm from the bottom of the paper with a pencil Make a small dot on the pencil line with each of the 3 ink pens that you are given as well as the unknown ink pen. (the criminal’s pen) Make the dots 1cm apart so that the colors won’t run together. Obtain a 500 mL beaker, then ask the instructor to pour some solvent in the beaker for you. Place your chromatography paper in the beaker so that the ink spots are at the bottom, but not touching the solvent. Place a piece of cardboard over the top of the beaker and observe what happens. Write your observations in the given section below. After 5 minutes, remove the filter paper from the beaker and allow it to dry. Compare the different ink spots to the unknown ink spot and determine what kind of pen wrote the ransom note. In the area provided below, draw a picture of your chromatogram and indicate which characteristics allowed you to identify the unknown ink pen. 2. Pencil Line 3. 4. 5. 6. 7. 8. 9.