Chemical reactions

• Acids are substances that produces hydrogen (H+) ions when dissolved in water. Most non-metal oxides are acidic ( H2O and CO are exceptions).

  • HCl -(hydrochloric acid)
  • HNO3 - (nitric acid)
  • H2SO4 - (sulfuric acid)
  • H3PO4 - (phosphoric acid)
  • H2CO3 - (carbonic acid)
  • CH3COOH - (ethanoic acid/vinegar)
• Acids have properties of (CSBE 7 (cosbie sweater))

  • tasting sour
  • being corrosive
  • turns blue litmus paper red
  • have a pH of less than 7
  • conductive to electricity.
• Salts are ionic compounds formed when an acid + base react - when the anion (negative ion) from the acid combines with the cation (positive ion) from the base.

  E.g. HCl + NaOH -> NaCl

  • Anion of acid is Cl-
  • Cation of base is Na+
• States

  • Solids - any metal, any insoluble compound
  • Liquid - water
  • Gas - non-metals which are gases
  • Aqueous (aq) - dissolved in water, any soluble compound
• 1. Acid + base -> salt + water
• 2. Acid + metal -> salt + hydrogen gas
• 3. Acid + carbonate/hydrogen carbonate -> salt + water + carbon dioxide
• Ionic equations only show species (molecules, ions, atoms) that participate in the reaction (they change state)
• Ions that don't participate in the chemical reaction (change state) are called spectator ions, and aren't included in ionic equations
• How to write ionic equations

  1. write the molecular equation including state symbols
  2. anything aqueous is split into ions, and everything else stays the same
  3. cancel out the spectator ions
  4. rewrite ionic equation without spectator ions and balance
• Why do we use moles?


  When chemical reactions occur, we have to count every single particle (atom, ion, molecule) that is involved in the reaction, but 1 gram of any substance contains a lot of particles, so it is more efficient to convert the number of particles to a 'collective' called a mole
• Avogadro's number?


  1 mole = 6.022 x 10^23 particles
• Formula to convert particles to moles?

  moles (n) = particles (N)/Avogadro's number (NA)
• Formula to convert moles to particles?

  Particles (N) = n x 6.022 x 10^23