If you add up the mass for one side it should equal the sum of the mass on the other side.
If not you messed up somewhere and need to review your work.
I was looking around Instructables and saw many chemistry related Instructables, so I thought one on stoichiometry would help.
Basically stoichiometry (my definition) is the study of amounts in relation to a chemical reaction.
Stoichiometry is the base for all modern chemistry.
The method I'm going to use is like a flow chart opposed to the "railroad tracks" that is taught by most teachers and books. The definition of combustion is a fuel when burned with oxygen produces only H2O and CO2.
Now multiple the number of moles by the coefficient of substance you find the moles of and divide it by the coefficient of the substance you are translating it into. You can now find find the mass of the product produced using the Sm/Mw=n equation. You can use the law of conservation of mass to do this.
Mass on both sides of the equation must be the same.
It only takes basic knowledge of the gas laws to know why this is.
Gas changes volume depending on temperature, and pressure. V- volume T- temperature k- constant Charles's law must be done in Kelvin because it is an direct variation.