What is stoichiometry?
 Stoichiometry is the quantitative study of reactants and products in a chemical reaction.

The proportions of reactants and products (the recipe) is referred to as the MOLE RATIO.
A mole ratio converts moles of one compound in a balanced chemical equation into moles of another compound.

Example
Reaction between magnesium and oxygen to form magnesium oxide.
2 Mg(s) + O
2
(g)
Mole Ratios:
2 : 1 :
2 MgO(s)
2

N
2
+ 3 H
2
2 NH
3
Write the mole ratios for N
2 to H
2 and NH
3 to H
2
.
Butane (C
4
H
10
) is a fuel used in BBQ lighters. Write out a balance reaction equation for the complete combustion of butane.
A can of butane lighter fluid contains 1.20 moles of butane calculate the number of moles of carbon dioxide given off when this butane is burned.

Equation of reaction
2C
4
H
10
+ 13O
2
8CO
2
+ 10H
2
O
Mole ratio
C
4
H
10
2 :
CO
2
8 [ from equation]
1.2 : X [ problem]
2 : 8 = 1.2 : X
Solving equivalent ratios, MEANS=EXTREMES
X = 4.8 mols of CO
2 given off

Homework
 Read section7.1
 Bottom half of handout from yesterday
 Page 319 #1-3
 Questions on pg 320 if more practice needed