Chapter 4 - Chemical Reactions

Formula Weight

sum of the atomic weight of all the atoms in the molecular formula

Mole

the quantity of a substance

Avogardo’s # (1 mole) =

6.02 × 10²³

Molar Mass =

atomic weight/formula weight in grams/mole

Moles to Atoms/ Molecules

Avo’s #

Moles to Grams

Molar Mass

Chemical Reaction

the formation of a new substance with a different composition and properties than the initial substance

Evidence of a Chemical Reaction

Color Changes, formation of a solid in a clear solution, formation of a gas (bubbles), evolution or absorption of heat, or emission of light

Balancing Chemical Equations

Atoms can neither be created or destroyed. (An equation must have the same number of and kind of atoms on both sides of the equation)

Mole-Mole Relationships

the coefficients in balanced reactions tell us how many moles of something will produce how many moles of something else

Mole A to Mole B

coefficient balanced ratio

Percentage Yield

% Yield = actual yield/ theoretical yield x 100

Actual Yield

actual quantity of product produced in the laboratory

Theoretical Yield

the quantity “in theory” of a product produced in a reaction (answer obtained from mass calculations)