Solubility Unit
British Columbia Ministry of Education (MOE) prescribed learning outcomes which apply to this
unit (www.bced.gov.bc.ca):
It is expected that students will:
Skills and Processes of Chemistry
A1 demonstrate appropriate safety techniques and proper use of protective equipment
A2 demonstrate skills in measuring and in recording data
A3 communicate results and data in clear and understandable forms
Mole Concept
C5 describe concentration in terms of molarity
C6 perform calculations involving molarity
Solution Chemistry
F1 distinguish between a solution and a pure substance
F2 predict the relative solubility of a solute in a solvent, based on its polarity
F3 relate ion formation to electrical conductivity in aqueous solutions
F4 calculate the concentration of ions in solution
Timeframe for unit: 20 class blocks
Lessons 1-5of 20 total:
Intended Learning Outcomes: Students will develop an understanding of solutions, specifically
PLOs A2, A3, C5, C6, and F4.
Day 1: Lab Day. Students will make “snow globes” and then try to explain their results. This will
allow me to assess prior knowledge, and will help me uncover any student misconceptions. The
activity is based on a discussion posting by Marc Herman. Instructions and materials list are
posted in Appendix 1.
Day 2: Define vocabulary terms using examples from everyday life. For example: Orange juice
from concentrate to explain concentrated and dilute. Use powerpoint presentation slides 1
through 4 to introduce various ways used to define concentration. Assign conversion worksheet
to be completed collaboratively.
Day 3: Use powerpoint slide 5, and a solubility worksheet to introduce and then practice
calculating equilibrium constants for slightly soluble simple salts.
Day 4: Use powerpoint slides 6 and 7, and Ksp and Q worksheets to introduce and then practice
calculating equilibrium constants and ion products for slightly soluble simple salts.
Day 5: Lab day. Use chemistry for life solubility lab. See attached pdf file.
(http://www.nwr1biology.com/pdfs/KNO3Lab.pdf) For homework ask students to reflect on the
week’s lessons, explaining what they have learned and what they now believe happened in their
snow globes. This reflection should be one typed page.
Appendix 1
Snow Globe Activity
Marc Herman
Materials needed for each group of two:
250 mL erlenmeyer flask
100 mL graduated cylinder
Hot glue gun
Baby food jar and lid
1g C6H5CO2H (benzoic acid)
Tap water
Decoration
Thermometer
Directions:
-In a 250 ml flask, stir 1 g benzoic acid into 75 ml of water.
-Heat the solution to dissolve the benzoic acid. You do not need to boil the water.
-Put down a bead of hot glue on the inside of the jar lid.
-Use tweezers or forceps to position your decoration in the glue.
-While the glue is cooling, watch your benzoic acid solution. Take pictures, or make drawings, of
your solution as it cools. At a minimum you will need three pictures, one when it is hot, one
when it is about 40oC, and one at 25oC. Be sure you label your pictures so that they are useful
in helping you describe what happens.
-Pour the room-temperature benzoic acid solution into the glass jar.
-Fill the jar as full as possible with water.
-Put the lid on the jar. Seal the jar with hot glue.
-Gently shake the jar, and describe what you see in words and with a picture.