Balancing Equations

  • Signs of Chemical Rxns: Color change, formation of gas, odor change, formation of precipitate

  • Signs of Energy Change: Absorbing or releasing heat, releasing light

  • In Normal Nuclear Energy Reactions:

    • Total Mass of reactants = total mass of products

    • Nothing can magically reappear or disappear

  • Written Equations: Equations written with the names of compounds. Ex: Hydrogen gas and chlorine gas combine to form Hydrogen Chloride gas

  • Skeleton Equations: Written with formulas. Ex: H2(g) + Cl2(g) → 2HCl(g)

  • Phases: Gas, Solid, Liquid, Aqueous (ions in water)

  • Diatomic Gases: Have No Fear Of Ice Cold Beer/Horses Need Oats For Clear Brown “I’s”. H2 N2 F2 O2 I2 Cl2 Br2

  • Balancing Tips:

    • Balance atoms that appear in the fewest places first

    • Try to leave diatomics for the end

    • Try to balance polyatomic ions as a chunk

    • In combustion reactions, place a 2 in front of hydrocarbon first and then count and balance. Sometimes you will need to reduce coefficients in the end but it is usually still easier to balance combustion reactions this way.

    • Count each atom: Before, During, and After