February 2 - Chemical Reactions Cont'd

We learned about the rest of the chemical reactions today which were: Double Replacement, Combustion, and Neutralization.


Double displacement: This is when the anions and cations of two different molecules switch places, forming two entirely different compounds. These reactions are in the general form: AB + CD ---> AD + CB

One example of a double displacement reaction is the reaction of lead (II) nitrate with potassium iodide to form lead (II) iodide and potassium nitrate:

Pb(NO₃)₂ + 2 KI ---> PbI₂ + 2 KNO₃

Combustion: A combustion reaction is when oxygen combines with another compound to form water and carbon dioxide. These reactions are exothermic, meaning they produce heat:
AB + O2  --> AO + BO

An example of this kind of reaction is the burning of napthalene:

C₁₀H₈ + 12 O₂ ---> 10 CO₂ + 4 H₂O

Acid-base: This is a special kind of double displacement reaction that takes place when an acid and base react with each other. The H⁺ ion in the acid reacts with the OH^- ion in the base, causing the formation of water. Generally, the product of this reaction is some ionic salt and water:            HA + BOH ---> H₂O + BA

One example of an acid-base reaction is the reaction of hydrobromic acid (HBr) with sodium hydroxide:HBr + NaOH ---> NaBr + H₂O


1)  Does your reaction have oxygen as one of it's reactants and carbon dioxide and water as products? If yes, then it's a combustion reaction
2) Does your reaction have water as one of the products? If yes, then it's an acid-base reaction
3) If you haven't answered "yes" to any of the questions, then you've got a double displacement reaction

Vids have low volume so turn it up a bit

Links that might help http://www.visionlearning.com/library/module_viewer.php?mid=54