Concepts
- When substances are mixed, mass is conserved, but volume might not be because particles fill gaps between each other.
- “Like dissolves like.” Whether a solute can dissolve in a solvent depends on a balance of attractive forces (solute-solvent vs. solvent-solvent and solute-solute). This means that polar substances tend to dissolve in other polar substances, and non-polar substances tend to dissolve in non-polar substances.
- When molecular (covalent) substances dissolve, their particles remain intact but separate from each other.
- When ionic solids dissolve, their ionic bonds are actually broken, producing free-floating ions. This is called dissociation.
- The concentration of a solution is measured in molarity, meaning mol/L.
- The greater the concentration of ions dissolved in water, the greater the electrical conductivity of the solution.
Skills
Quiz 5a
- Based on polarity or ionic charge, predict whether a covalent or ionic species will dissolve in a given solvent.
- Determine the concentration of a solution.
- Perform dilution and mixing calculations.
Quiz 5b
- Describe the effect of a solvent on electrical conductivity.
- Perform stoichiometric calculations involving solutions.
Homework
Quiz 5a
- 5a.1 Predicting solubility (“like dissolves like”)
- 5a.2 Concentration
- 5a.3 Dilution problems
- 5a.4 Making solutions (includes dilution)
Quiz 5b
- 5b.1 Solution stoichiometry (includes notes)
- 5b.2 Solution stoichiometry 2
Projects & Labs
Quiz 5a
- Lab 5a.1: Like dissolves like
- Lab 5a.2: Preparing a Solution
Quiz 5b
- Lab 5b.1: Conductivity of Gatorade (may need modification)
- Lab 5b.2: Limiting reactant and percent yield in a precipitation reaction
Assessment
- Quiz 5a: Solubility, concentration, dilutions
- Quiz 5b: Conductivity, solution stoichiometry
- Test 5: Solutions
