Jove Lab Chem
Recrystallization — Lab Prep
Source: Lara Al Hariri at the University of Massachusetts Amherst, MA, USA
- Preparation of the Laboratory
Here, we show the laboratory preparation for 10 students working in pairs, with some excess. Please adjust quantities as needed.
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To set up for this lab experiment, wear the appropriate personal protective equipment, including a lab coat, chemical splash goggles, and gloves.
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Confirm that the lab has a glass waste container and a container for solid acetanilide and trans-cinnamic acid waste.
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Prepare 40 mL of a 95% by volume ethanol solution. Measure 38 mL of absolute ethanol and pour it into a 50-mL glass bottle using a funnel.
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Then, add 2 mL of deionized water to the bottle. Mix the solution with a glass rod or by shaking the closed bottle until it appears homogeneous.
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Label the bottle and place it in a fume hood for solvents. Store the absolute ethanol in a cabinet for flammable materials.
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Set aside high-purity acetanilide and trans-cinnamic acid to be used as seed crystals.
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Bring reagent-grade acetanilide and trans-cinnamic acid to the balances for students to use. Confirm that there are enough lab wipes, spatulas, and weighing boats.
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Set out the following glassware and equipment at each student lab station:
1 Lab stand 1 3-prong clamp 1 Stirring hotplate 1 Pair of flask tongs 1 Vacuum pump (or house vacuum) 1 125- or 250-mL filter flask 2 Büchner funnels 1 Filter adapter 2 600-mL beakers 1 250-mL beaker 2 5-mL graduated cylinders 1 10-mL graduated cylinder 1 125-mL Erlenmeyer flask* 1 25-mL Erlenmeyer flask 2 Glass stirring rods 1 Medium stir bar 1 Pair of tweezers 2 Pipette bulbs -
Keep extra 125-mL Erlenmeyer flasks, stemless or wide-stem glass funnels, large filter papers, small beakers, and boiling chips available in case students need to hot filter their acetanilide solutions.
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Place boxes of laboratory wipes, medium filter papers, and Pasteur pipettes in a central area for the students.
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Set up the melting point analyzer and place a container of capillaries next to it.
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Just before the lab, fill an insulated cooler with about 8 L of crushed ice. Place the cooler and an ice scoop on the central bench in the lab.
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