Chemical equation: Reactants -> Products

Balancing rules:

1. Write correct formulas for all reactants and products
2. Count atoms of each element on both sides
3. Add coefficients to balance (NEVER change subscripts)
4. Check polyatomic ions as units if unchanged
5. Verify lowest whole-number ratio

Spectator ions: Ions that do not participate in reaction (appear unchanged on both sides) Precipitate: Insoluble solid formed in solution

Net ionic equation: Shows only species that actually change

• Omit spectator ions
• Include states of matter: (s) solid, (l) liquid, (g) gas, (aq) aqueous

Limiting reactant: Reactant that produces least amount of product (runs out first) Excess reactant: Reactant remaining after limiting reactant consumed

Procedure:

1. Convert given quantities to moles
2. Use mole ratios to calculate moles of product from each reactant
3. Limiting reactant determines theoretical yield

Theoretical yield: Maximum amount of product possible (from limiting reactant) Actual yield: Amount of product actually obtained Percent yield: $\frac{\text{actual}}{\text{theoretical}} \times 100\%$

Titration: Laboratory technique to determine concentration of unknown solution

• Burette: Delivers titrant (known concentration)
• Erlenmeyer flask: Contains analyte (unknown concentration)
• Indicator: Changes color at equivalence point
• Equivalence point: Moles acid = moles base

Acid-base: Neutralization reaction producing water and salt Redox: Electron transfer between species Precipitation: Formation of insoluble solid

Oxidation number rules:

1. Pure element = 0
2. Monoatomic ion = charge
3. O = -2 (except -1 in peroxides)
4. H = +1 (except -1 in metal hydrides)
5. F = -1
6. Sum = overall charge

Half-reactions: Separate oxidation and reduction processes

1. Split into half-reactions
2. Balance atoms (add H2O for O, H+ for H)
3. Balance charge with e-
4. Equalize electrons transferred
5. Add half-reactions
6. Cancel species appearing on both sides