Jove Lab Chem

Scientific Measurement and Lab Skills — Lab Prep

Source: Smaa Koraym at Johns Hopkins University, MD, USA

1. Preparation of the LaboratoryExpand

   Here, we show the laboratory preparation for 10 students working individually, with some excess. Please adjust quantities as needed.

   • To set up for this lab experiment, wear the appropriate personal protective equipment, including a lab coat, chemical splash goggles, and gloves.
   • Prepare a 1.5 x 10^-5 M erythrosin B red dye solution. To prepare 500 mL of this solution, weigh 0.0066 g of erythrosin B on an analytical balance.
   • Transfer the erythrosin B to a 250-mL Erlenmeyer flask. Then, measure 200 mL of deionized water and add it to the flask. Place a magnetic stir bar in the flask, set the flask on a stir plate, and mix the solution until it appears homogeneous.
   • Use a funnel to pour the solution into a 500-mL volumetric flask, and carefully fill the flask to the line using deionized water. Seal the top of the flask with paraffin film and invert it several times until the solution is well-mixed.
   • Label a 500-mL squeeze bottle with the concentration and transfer the solution into the bottle. Store the bottle on a mat in the hood. Note: Take significant figures into account.
   • Place acetone in an area so that students have access to it during the lab. Note: Each student will need about 40 mL.
   • Set weigh boats, scoops, and a container of sand next to a balance. Note: Each student will need about 3 g.
   • Place an organic waste container in a central hood.
   • Set out the following glassware and equipment at each student lab station (we suggest students work independently during this lab):

     1    50-mL beaker

     1    100-mL beaker

     1    250-mL beaker

     1    400-mL beaker

     1    600-mL beaker

     1    500-mL filter flask

     1    Büchner funnel

     1    10-mL graduated cylinder

     1    Watch glass

     1    5-mL volumetric pipette

     1    10-mL volumetric pipette

     1    10-mL capacity pipetter

     1    10-mL volumetric flask

     1    String (18 in)

     1    Silicone vacuum tubing (18 in)

     1    12-in ruler

     1    Rubber adapter

     1    Rubber stopper

     1    Glass stirring rod

     1    Rubber policeman

     1    Disposable pipette

     1    Bottle of deionized water

     1    Lab mat

     1    Box of filter papers (1 filter paper per student)