Stoichiometry Devon Bateman

Essential Question Why is a foot…a foot? –King Henry I had a foot 12 inches long.

Unit Questions What are measurements? What do we measure? How do we measure? Why do we measure? How do chemists measure molecules?

Overview Measurement –List examples of measurement –Define purpose of measurement –Explain chemist’s use of the mole Stoichiometry –Relate stoichiometry to a recipe –Demonstrate mole ratios in balanced equations

WHAT DO WE MEASURE AND HOW?

Measurements allow us compare or analyze data. Therefore, measurements must be reasonable.

How do chemists count molecules? Can chemists count by measuring? Chemists count using the mole.

Mole: the unit used to measure the amount of a substance 1 mole = 6.02x10 23 particles

Stoichiometry- the study of mole and mass relationships in a chemical reactionStoichiometry-

The mass of the reactants must equal the mass of the products. H 2 + Cl 2  2 HCl

A balanced chemical equation is very similar to a recipe.

Coefficients represent the mole ratio between substances. 6 O 2 + C 6 H 12 O 6  6 CO H 2 O

Example 4 Fe + 3 O 2  2 Fe 2 O 3 It takes 4 moles iron & 3 moles oxygen to produce 2 moles iron (III) oxide.

Conclusion The mole allows chemists to analyze chemical reactions. Balanced equations can be treated like recipes. Amount of ingredients determines the amount of product