Balancing Equations

Today, we learned about chemical equations!

- Formulas must be correct or nothing will be right

there are different types of reactions:


combustion: when oxygen combines with another compound to form carbon dioxide and water
C₃H₄ + O₃ ---> CO₂ + H₂O

synthesis: when two compounds combine to form a more complicated one
A + B --> AB

decomposition: when a complex molecule breaks down to make simpler ones
AB --> A + B

single replacement: When one element trades places with another in a compound.

A + BC --> AC + B (if A is a metal)
A + BC --> BA + C (if A is non-metal)

double replacement: When metals and non metals of an element switch places
AB + CD --> AD + CB

Acid-Base Neutralization: When an acid and base react to make a salt and water
HBr + NaOH ---> NaBr + H₂O

We balanced equations.... here's how!!
1. make sure all formulas are correct with correct subscripts
2. count how many of each element there is on each side
3. place coefficients beside compounds (and individual elements, if any) to make each element have the same number of each side
4. if oxygen is one of the elements present, do it last
5. check your answers!!!

here are a few examples

___ NaNO₃ + ___ PbO ---> ___ Pb(NO₃)₂ + ___ Na₂O
becomes
2 NaNO₃ + PbO ---> Pb(NO₃)₂ + Na₂O

AgI + Fe₂(CO₃)₃ --> FeI₃ + Ag₂CO­₃

becomes

6 AgI + Fe₂(CO₃)₃ --> 2 FeI₃ + 3 Ag₂CO­₃

C₂H₄O₂ + O₂ --> CO₂ + H₂O

becomes
C₂H₄O₂ + 2 O₂ --> 2 CO₂ + 2 H₂O

heres a worksheet!