chemistry test

Law of Conservation of Mass

Matter cannot be created or destroyed; the number of atoms must be equal on both sides.

Balance by adding coefficients in front of

compounds

Chemical Equilibrium

When the rate of the forward reaction equals the reverse reaction

Concentrations of reactants and products remain

constant (not necessarily equal)

Le Châtelier’s Principle:

If a system at equilibrium is disturbed, it will shift to minimize the disturbance:

Add reactant OR Remove product

shifts to product side

Change temperature

depends on exo-/endothermic reaction

increasing temperature

endothermic

decreasing temperature

exothermic

strong electrolyte

These completely dissociate into ions when dissolved in water. They are good conductors of electricity

weak electrolyte

These only partially dissociate into ions in water. They are poor conductors of electricity compared to strong electrolytes

non electrolyte

These do not dissociate into ions at all when dissolved in water. They do not conduct electricity

• NaCl (Sodium chloride)

  • Dissociates into: Na⁺ + Cl⁻

• HCl (Hydrochloric acid)

  • Dissociates into: H⁺ + Cl⁻

• KNO₃ (Potassium nitrate)

  • Dissociates into: K⁺ + NO₃⁻

• H₂SO₄ (Sulfuric acid)

Dissociates into: 2H⁺ + SO₄²⁻

example of a strong electrolyte

• CH₃COOH (Acetic acid)

  • Partially dissociates into: H⁺ + CH₃COO⁻

• NH₃ (Ammonia)

  • Partially dissociates into: NH₄⁺ + OH⁻

• HF (Hydrofluoric acid)

  • Partially dissociates into: H⁺ + F⁻

• H₂O (Water) (in a very tiny amount, but it does dissociate)

Partially dissociates into: H⁺ + OH⁻

example of a weak electrolyte

• C₆H₁₂O₆ (Glucose)

  • Does not dissociate, stays as glucose molecules.

• C₂H₅OH (Ethanol)

  • Does not dissociate, stays as ethanol molecules.

• CH₃OH (Methanol)

  • Does not dissociate, stays as methanol molecules.

• Urea (NH₂CONH₂)

Does not dissociate, stays as urea molecules.

example of a non electrolyte