Solubility — Lab Prep

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

  1. Lab Preparation for Determining the Solubility of Borax

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

    • Assign each of the lab groups a temperature of either 10, 20, 30, 40, or 50 °C. Note: There can be duplicates for larger class sizes.
    • Place a stock bottle of borax, weighing boats, and a spatula at each weigh station.
    • Prepare one dropper bottle containing 1-2 mL of 0.1% bromocresol green indicator for each lab group.
    • Prepare a 0.5 M solution of HCl. For 500 mL, use a volumetric pipette to transfer 20 mL to a 500-mL volumetric flask. Dilute the solution to the 500-mL mark with deionized water, and mix the solution on a stir plate until it appears homogeneous. Transfer the solution to a bottle and store it in an appropriate location until the lab session.
    • Set out the following glassware for each student group (we suggest that students work in pairs):
       1    Ring stand
       1    Burette clamp
       1    50-mL glass burette
       1    Thermometer clamp
       1    Digital thermometer
       1    Glass thermometer
       1    Long-stem funnel
       1    5-mL volumetric pipette
       1    10-mL capacity pipetter
       1    50-mL graduated cylinder
       5    250-mL Erlenmeyer flasks
       2    400-mL beakers
       1    150-mL beaker
       1    Stirring hotplate
       1    Stir bar