Chemistry: Concentration of Solutions and Normality

Insoluble Salts of Silver

• All silver salts are insoluble, except for AgNO3 and AgClO4, which are soluble, and AgC2H3O2 and Ag2SO4, which are moderately soluble.

Factors Affecting Solubility

• A solvent can only dissolve a limited quantity of solute at a definite temperature.
• The rate of dissolving solids can be increased by:
  • Pulverizing or grinding up the solid to increase the surface area
  • Heating the solvent to increase molecular motion
  • Stirring vigorously
• Combinations of these methods can accelerate the dissolving process.

Definitions

• Solute: The substance that is dissolved or has gone into solution (typically a solid).
• Solvent: The substance that does the dissolving (typically a liquid, such as water or alcohol).
• Solution: A uniform homogeneous mixture of two or more substances.
• Normality (N): A concentration unit defined as the number of equivalents of solute per liter of solution.
• Standard Solution: A very precise solution, usually to 3-4 significant figures, used in quantitative analysis or analytical procedures.
• Supersaturated Solution: A solution that contains more solute than equilibrium conditions allow, which is unstable and may precipitate upon slight agitation or addition of a single crystal.

Preparation of Solutions

• To prepare a standard solution, add solid to acid solution, stir, then add to water, and dilute to 1 L.
• To prepare a saturated solution, add solute to water until it no longer dissolves, then stir for 1 hour and filter.

Labeling and Safety

• Always label chemicals clearly and permanently with:
  • Identity of contents
  • Concentration
  • Date of preparation (if applicable)
  • Hazard alert (if applicable)
  • Your name