Unit 4 lesson 23 & 24

Lesson 23 - Precipitation Reactions

Precipitate- a solid produced in a chemical reaction between two solutions

Substances with low solubility tend to form precipitates in aqueous solutions

Most reactions involve double exchange reactions with ionic compounds where the cations exchange anions.

Lesson 24 - Mole Ratios
Coefficients in chemical equations refer to the number of units like molecules, moles, or ions that are combining.

Mole ratio- ratio represented by the coefficients in a chemical equation showing how many units of each substance must combine to make the maximum amount of product.

Reactants combined in a imperfect mole ratio run out of one while leaving behind more of the other:

        - limiting reactant - runs out

        - excess reactant - leaves more behind

When comparing the two reactants, compare the moles to find out which is limiting and which is excess. Don't use the coefficients.

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