Writing Chemical Equations & Balancing Them

***Please Watch the Videos Below before Attempting any Problems***

Reactants--> Products

The reactants will always be on the left and the products on the right.

Using the 5 Types of Chemical Reactions you can correctly predict the products of a chemical reaction.

1. Synthesis A + B --> AB Mg + O2-->MgO Whenever there are compounds by themselves that are fused together this is synthesis.

2. Decomposition AB--> A + B H2O2 --> H2O + O2 Synthesis is the opposite of decomposition. Going from one compound to more than one

3. Single Displacement A + BC --> AC + B Al + CuCl2 --> AlCl3 + Cu Any element by itself replaces one of the elements inside of an ionic bond

4. Double Displacement AB + CD --> AD + CB PbNO3 + KI --> KNO3 + PbI Looking at this reaction you see the metals and non-metals switch partners. Remember metal must be bonded to a nonmetal. You cannot put two metals together!

5. Combustion Fuel + O2 --> CO2 + H2O Usually a hydrocarbon (CH4 for example) reacts with oxygen and in most cases makes CO2 and H2O and a large release of energy. (FIRE!!!)

Limiting Reactants

Think about Bicycle workshop. If you went into business and the supply chain gave you 5 bike frames, but only 8 wheels. How many bicycles could you make? With the 5 bike frames you could make 5 bikes. However with the 8 wheels (2wheels/bike), you could only create 4 bikes. Based on that information you would have an extra bike frame with no wheels to go on it. Therefore even though you have an extra bike bike frame the wheels are limiting how many bikes you could actually make. So in this example you can only make 4! This applies to chemicals too. Watch the video below for an example how this works!

Empirical and Molecular Formulas From Percent Composition