Feb.2--Types or Reactions (Part 2)

Double Replacement: a reaction between two ionic compounds (usually in solution).

AB + CD --> CB + AD

Note: Remember that a metal always combine with a non-metal!

Ex. Na₂CO₃ + CaCl₂ --> CaCO₃ + 2 NaCl

To determine if a double replacement reaction actually occurs, use your “Table of Solubility” to check if the reactants change state. If there is no change of state, the reaction won’t occur.

How To Use the Table of Solubility

Step 1. Find your anion (negative ion) in the left hand column.

Step 2. Find your cation (positive ion) in the second column.

Step 3. Check to see if the compound is soluble or not.

Step 4. If soluble, the compound is (aq); if insoluble, the compound is (s).

Net Ionic Equation

- There is a net reaction when you have a precipitation that occurs.

- (aq) ions that are the same on both sides get cancelled

Ex. 2 Na₃PO₄ + 3 Ca(NO₃)₂ --> 6 NaNO₃(aq) + Ca₃(PO₄)₂(s)

   net ionic equation: 3 Ca²⁺(aq) + 2 PO₄^3-(aq) --> Ca₃(PO₄)₂(s)

Combustion: a reaction where burning in air is involved. The reactants are the chemicals to be burned (organic compound) and the oxygen that it reacts with. They usually produce carbon dioxide and water.

AB + O2 --> AO + BO

Ex. C₄H₈ + 6 O₂ --> 4 CO₂ + 4 H₂O

Neutralization: acid react with base to produce water and an ionic salt. (Double Replacement)

Note: Both acid and base should be aqueous solutions!

HA + BOH --> H₂O + BA

Ex. 2 HBr(aq) + Sr(OH)₂(aq) --> SrBr₂(aq) + 2 H₂O(l)