Chemistry: Reactivity and Salts

Reactivity and Salts

Acid-Base Reactions

• Acid: a substance that donates a proton (H+)
• Base: a substance that accepts a proton (H+)
• Acid-base reactions involve the transfer of a proton from an acid to a base
• Examples:
  • HCl (acid) + NaOH (base) → NaCl (salt) + H2O
  • H2SO4 (acid) + KOH (base) → K2SO4 (salt) + H2O

Ionic Compounds

• Formed from the reaction between a metal and a nonmetal
• Metal loses one or more electrons to form a cation (positive ion)
• Nonmetal gains one or more electrons to form an anion (negative ion)
• Cation and anion combine to form a neutral compound
• Examples:
  • Na (metal) + Cl (nonmetal) → NaCl (salt)
  • Ca (metal) + O (nonmetal) → CaO (salt)

Neutralization Reactions

• A type of acid-base reaction where an acid and a base react to form a salt and water
• The pH of the solution is neutralized (pH = 7)
• Examples:
  • HCl (acid) + NaOH (base) → NaCl (salt) + H2O
  • H2SO4 (acid) + KOH (base) → K2SO4 (salt) + H2O

Oxidation States

• The number of electrons gained or lost by an atom in a reaction
• Can be positive (oxidation) or negative (reduction)
• Oxidation states can be used to identify the species involved in a reaction
• Examples:
  • Na (metal) loses one electron to form Na+ (oxidation)
  • Cl (nonmetal) gains one electron to form Cl- (reduction)

Solubility Rules

• A set of rules to predict whether an ionic compound is soluble or insoluble in water
• Rules:
  • All sodium, potassium, and ammonium salts are soluble
  • All nitrates and acetates are soluble
  • Chlorides, bromides, and iodides are soluble except for those of silver, lead, and mercury
  • Sulfates are soluble except for those of calcium, strontium, and barium
  • Hydroxides and oxides are insoluble except for those of sodium, potassium, and ammonium