Solubility of Salts

This experiment explores the solubility of different household compounds in water. By adding each compound gradually until no more dissolves, students discover the concept of saturation and compare how different substances dissolve in the same solvent.

1. Label two cups for each substance: salt, sugar, baking soda, and Epsom salt.
2. Measure out approximately 20 g baking soda, 50 g table salt, 150 g Epsom salt, and 250 g table sugar into one cup of each pair. Record the masses.
3. Measure 100 mL of distilled water into the second cup of each pair. Ensure the water is at room temperature.
4. For baking soda: add one teaspoon of baking soda at a time into the cup of water, stirring after each addition until it no longer dissolves and remains visible. Note how many spoonfuls dissolved.
5. Repeat this process for Epsom salt, table salt, and sugar, using clean spoons for each.
6. Weigh each remaining solid cup after the experiment and subtract from the initial mass to calculate how much of each compound dissolved.
7. Compare results to determine which substance was most and least soluble.
8. Dispose of the mixtures in the sink and wash all equipment thoroughly.

📄 Solubility Science: How Much is Too Much? - Svenja Lohner: https://www.sciencebuddies.org/stem-activities/solubility-limits

• Repeat the experiment using different solvents such as rubbing alcohol, vegetable oil, or nail polish remover.
• Test solubility at different water temperatures (cold, room temperature, hot).
• Try other household substances like cocoa powder or flour to see which are soluble or insoluble.
• Record solubility data graphically to compare across different compounds.

• Wash hands thoroughly after handling the materials.
• Do not ingest or taste any substances used in the experiment.
• Dispose of mixtures properly—pour down the sink with running water.
• Handle glassware carefully to avoid breakage.
• If using hot water for variation experiments, take care to prevent burns.

• Which compound dissolved the most in water? (Sugar.)
• Which compound was least soluble? (Baking soda.)
• What does it mean when a solution becomes saturated? (No more solute can dissolve at that temperature.)
• Why do some compounds dissolve better than others? (Differences in molecular structure and bonding affect how easily water molecules can break solute bonds.)
• Would heating the water increase solubility? Why or why not? (Yes, because higher temperatures provide more energy to break molecular bonds and dissolve more solute.)