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WHAT IS STOICHIOMETRY1/6/12
Chapter 12Section 12.1
What is Stoichiometry
It is the study of quantitative relationships between amounts of reactants used and products formed by a chemical reaction.
For example: To help you answer the question: “ How much oxygen is required to burn a candle completely that has a certain mass.
This is based off of the law of conservation.What is the law of conservation?First determine the molar mass for the
reactant and product of the following:
4Fe + 3O2 2Fe2O3
Your answers should be for your reactant 319.4 g/mol
Your product 319.4 g/molTherefore, the law of conservation means
that the mass that you begin with is the same mass you end with.
USING STOICHIOMETRY
Section 12.2Stoichiometric Calculations
Purpose of Stoichimetry
Ingredients3/4 cup butter 1 1/2 cups brown sugar 2 tablespoons water 2 cups semisweet chocolate chips 2 eggs 2 1/2 cups all-purpose flour 1 1/4 teaspoons baking soda 1/2 teaspoon salt 3 (4.5 ounce) packages chocolate covered thin
mintsMakes 40 cookies
Steps to take
1. Balance the equation (if needed)2. Place values above the given and X above
the unknown3. Cross multiply and solve for X (the
unknown)
Mole to Mole Conversion
Your key equation here is:Moles given x mole ratioExample:
2 C8H18 + 25 O2 16 CO2 + 18 H2O
How many moles of O2 are needed to react fully with 4 moles of octane?
2 C8H18 + 25 O2 16 CO2 + 18 H2O
How many moles of CO2 can form from 1 mole of octane?
2 C8H18 + 25 O2 16 CO2 + 18 H2O
How many moles of water are produced by the combustion of 6 moles of octane?
How many moles of iron, Fe, can be made from Fe2O3 by the use of 18 moles of carbon monoxide, CO, in the following reaction?
1 Fe2O3 + 3 CO 2 Fe + 3 CO2
How many moles of H2O are produced when 6 moles of O2 is consumed in burning methyl alcohol, CH3OH, according to the following equation?
2 CH3OH + 3 O2 2 CO2 + 4 H2O