BBC

1
Stoichiometry
If you had some eggs, flour, and sugar lying
around the house and you wanted to make a cake,
what would you do? How much cake could you make
with the ingredients you already have? If
you had to make 5 cakes, what would you do? How
much material (eggs, flour, sugar) do you need to
make 5 cakes?
2
Stoichiometry
-Atoms are neither created nor destroyed in a
chemical reaction. -It is possible to calculate
the mass of any one of the products or of any one
of the reactants if the mass of just one reactant
or product is known using a balanced equation.
-the coefficients in the balanced chemical
equation are mole quantities, not masses.
3
Stoichiometry
2 H2 O2 ? 2 H2O Ex Given the equation above,
how many grams of water will be obtained by
combining 5.0 grams of hydrogen gas with an
excess of oxygen gas? mass ? mass
known ? known ? unknown ? unknown
mass moles moles
mass Example Setup
Mole Ratio (always present)
4
Stoichiometry
Other ways of doing stoichiometry mass ?
moles known mass ? known moles ? unknown moles
moles ? mass known moles ? unknown moles ?
unknown mass
5
Stoichiometry
moles ? moles known moles ? unknown moles