Solubility

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