Acids

• Acids


  Substances that conduct electricity in water solutions due to their degree of ionization
• Acids classified by degree of ionization


  • Completely or Nearly Completely Ionized: Nitric, Hydrochloric, Sulphuric, Hydriodic, Hydrobromic
  • Moderately Ionized: Oxalic, Phosphoric, Sulphurous
  • Slightly Ionized: Hydrofluoric, Acetic, Carbonic, Hydrosulphuric
• Acids


  • React with metals more active than hydrogen to liberate hydrogen
  • Change the color of indicators like litmus and phenolphthalein
  • React with bases to form water and a salt (neutralization)
  • Have a sour taste if in a weak solution
  • React with carbonates to release carbon dioxide
• Arrhenius theory of acids

  Acids are substances that yield hydrogen ions in aqueous solution
• Bronsted-Lowry theory of acids

  Acids are species (molecular or ionic) that can donate a proton to another species
• According to Bronsted-Lowry theory, free hydrogen ions (protons) do not exist in solution, instead they bond with water molecules to form hydronium ions (H3O+)
• Strong acids


  • Hydrohalic acids (HCl, HBr, HI)
  • Oxoacids where number of O atoms exceeds number of ionizable protons by 2 or more (HNO3, H2SO4, HClO4)
• Weak acids


  • Hydrohalic acid HF
  • Acids where H is not bonded to O or halogen (HCN, H2S)
  • Oxoacids where number of O atoms equals or exceeds number of ionizable protons by 1 (HClO, HNO2, H3PO4)
  • Carboxylic acids (CH3COOH, C6H5COOH)
• Strong bases


  • M2O or MOH where M is a Group 1 metal (Li, Na, K, Rb, Cs)
  • MO or M(OH)2 where M is a Group 2 metal (Ca, Sr, Ba)
• Weak bases


  • Ammonia (NH3)
  • Amines (RNH2, R2NH, R3N)
• Neutral (uncharged) atom

  Number of electrons equals the number of protons, so the overall charge is zero
• When the protons and electrons are not equal


  The overall charge is not zero
• Positive charge


  Atom contains fewer electrons than protons
• Negative charge

  Atom contains more electrons than protons
• Ion

  Atom contains more or less electrons than protons, and has a charge
• Elements that exist naturally as ions

  • Sodium
  • Calcium
• Elements that exist naturally as neutral atoms

  • Gold
• Cation

  Positively charged ion that contains fewer electrons than the number of protons in the nucleus
• Cation


  • Calcium ion, Ca2+
• Anion


  Negatively charged ion that contains more electrons than the number of protons in the nucleus
• Anion

  • Chloride ion, Cl-
• Formation of ions from neutral atoms

  1. Magnesium atom loses two electrons to form Mg2+ cation

  2. Nitrogen atom gains three electrons to form N3- anion
• Ionic compound


  Composed of ions, charged particles that form when an atom (or small group of atoms) gains or loses one or more electrons
• Binary ionic compound

  • Composed of just two elements, typically forms when a metal reacts with a nonmetal
• Monatomic ion


  Ion derived from a single atom
• Polyatomic ion


  Ion derived from a small group of atoms