In-Depth Notes on Solutions for 10th Grade Chemistry

SOLUTIONS

• Definition: A homogeneous mixture.

• Components:

  • Solute: The substance that is dissolved.

  • Solvent: The medium that dissolves the solute.

TYPES OF SOLUTIONS

• Gas in Gas: Air (composition: nitrogen, oxygen, argon)

• Liquid in Gas: Humid air (water vapor in air)

• Solid in Gas: Smog

• Gas in Liquid: Carbonated drinks

• Liquid in Liquid: Vinegar (acetic acid in water)

• Solid in Liquid: Salt water

• Gas in Solid: Styrofoam

• Liquid in Solid: Dental amalgam (mercury in silver)

• Solid in Solid: Sterling silver (copper in silver)

HOW DOES A SOLUTION FORM?

• When sodium chloride (NaCl) is placed in water:

  • Water molecules surround and interact with the NaCl crystal.

  • Water separates the positive ions (cations) and negative ions (anions).

  • Cations are surrounded by negatively charged oxygen in water.

  • Anions are surrounded by positively charged hydrogen in water.

SOLUBILITY

• Definition: The ability of a solute to dissolve in a solvent to form a solution.

DISSOLVING/DISSOCIATION EQUATIONS

• Dissociation: The process when an ionic compound breaks into ions in a solvent.

• Dissociation equations must represent the process accurately.

FACTORS AFFECTING SOLUBILITY

• Phases of Matter:

  • Solids: Strong intermolecular forces (IMFs) make solubility harder.

  • Liquids: Weaker IMFs allow mixing with solvents.

  • Gases: Weakest IMFs lead to higher solubility.

• Quantity of Solvent:

  • Increased solvent volume can boost dissolution but has limits.

• Polarity:

  • "Like dissolves like": Polar solutes dissolve in polar solvents; nonpolar solutes in nonpolar solvents.

  • Example:

  • Polar solute (e.g., C12H22O11) soluble in polar solvent; Nonpolar solute (e.g., C10H8) insoluble in polar solvents.

• Pressure:

  • Increased pressure enhances gas solubility in liquids; negligible effect on solids and liquids.

• Temperature:

  • Generally, higher temperatures increase solid and liquid solubility; may decrease gas solubility.

SOLUBILITY RULES

• Solubility Predictions:

  • Solubility rules indicate which ionic compounds will dissolve in water.

  • Alkali metals, ammonium, nitrates, and acetates are usually soluble; carbonates, phosphates, sulfides, and hydroxides are not.

• Ions Forming Soluble Compounds (with Exceptions):

  • Group 1 ions, ammonium, nitrates, acetates, hydrogen carbonate, chlorates, halides, sulfates (with specific exceptions).

• Ions Forming Insoluble Compounds (with Exceptions):

  • Carbonates, chromates, phosphates, hydroxides, sulfides (with specific exceptions).

SOLUBILITY CURVES AND SATURATION

• Saturated Solution: Contains maximum solute at a given temperature.

• Unsaturated Solution: Contains less than maximum solute.

• Supersaturated Solution: Contains more than maximum solute.

SUPERSATURATION

• Adding a single crystal to a supersaturated solution leads to rapid crystallization.