Overview
This lecture explains electrolytes, including their definition, types (strong, weak, nonelectrolytes), how they conduct electricity, and the processes for ionic and covalent electrolytes.
Electrolyte Basics
- Electrolytes are substances that yield ions in solution and conduct electricity when dissolved in water.
- Nonelectrolytes do not produce ions when dissolved, so their solutions do not conduct electricity.
- Strong electrolytes fully convert to ions in solution; weak electrolytes only partially do so.
Measuring Electrolyte Strength
- The strength of an electrolyte is determined by measuring the electrical conductivity of its aqueous solution.
- Solutions conduct electricity if they contain freely moving charged species (ions).
- Conductivity increases with ion concentration in the solution.
- Devices like electrodes and light bulbs can be used to assess the presence and concentration of ions.
Ionic Electrolytes
- Ionic compounds dissolve in water through ion-dipole attractions between ions and water molecules.
- The process of dissolving ionic compounds is called dissociation, a physical change resulting in solvated ions.
- Most ionic compounds dissociate almost completely, therefore are strong electrolytes.
- Even sparingly soluble ionic compounds are considered strong electrolytes if the part that dissolves dissociates fully.
Covalent Electrolytes
- Pure water conducts electricity poorly because it ionizes only very slightly.
- Some covalent compounds (like HCl) react chemically with water, producing ions and conducting electricity.
- HCl in water (a strong acid) ionizes completely to form hydronium (H₃O⁺) and chloride ions (Cl⁻).
- Weak acids and bases ionize only partially in solution, making them weak electrolytes.
Key Terms & Definitions
- Electrolyte — a substance that produces ions in solution and conducts electricity.
- Nonelectrolyte — a substance that does not form ions in solution and does not conduct electricity.
- Strong Electrolyte — a compound that fully dissociates into ions in solution.
- Weak Electrolyte — a compound that only partially dissociates into ions in solution.
- Dissociation — the physical process where an ionic compound separates into its ions in solution.
- Ion-Dipole Attraction — the force of attraction between an ion and a polar molecule.
Action Items / Next Steps
- Review the differences in dissolution for ionic and covalent electrolytes.
- Practice identifying strong, weak, and nonelectrolytes using conductivity examples.
- Read the next section on solubility for further context.