# Stoichiometry

### By:Fernando Acte

## Balancing a equation

To solve a Stoichiometry problem you have to look at the two elements given and find out what type of reaction it is. Then the next step would be to balance out the equation and write the states of matter. For example if Barium Hydroxide-

**Ba(OH)2**and Aluminum Nitrate-**Al(NO3)3**are given, then this would be a double replacement reaction. This means that Barium and and Aluminum would change spots making Barium Nitrate-**Ba(No3)2**and Aluminum Hydroxide-**Al(OH)3**. The final step would be to balance it out by adding coefficients.## Figuring out molar mass

To find out the molar mass you will need a periodic table, and a calculator is optional. First find the mass of every element and multiply it by the subscript(which is the small # on the equations).Remember that if there are two subscripts-one on the inside of the equation and one on the outside- the first element gets the subscript on the outside, and the second element gets the two subscripts multiplied with each other. So in our example The molar mass of Ba(OH)2 is 171.342 g/mole, Al(NO3)3 is 212.994 g/mole, Ba(No3)2 is 309.333g/mole, and Al(OH)3 is 339.339g/mole.

## Limiting reactant This is the reactant that limits the amount of a chemical reaction we can make | ## How to Calculate Reactant and excess Use the formula in the picture above. Whichever one u have the least of is the theoretical which means that's the least product you can make from the reactants given. The limiting is the reactant that will run out first. Then the excess is the reactant that you have more than enough. | ## excess reactant This is the reactant that we have more than enough to make a chemical reaction |

## How to Calculate Reactant and excess

Use the formula in the picture above. Whichever one u have the least of is the theoretical which means that's the least product you can make from the reactants given. The limiting is the reactant that will run out first. Then the excess is the reactant that you have more than enough.

Stoichiometry - Chemistry