WARM UP “A ship in the harbor is safe, but that is not what ships are built for.” –William Shedd 1.What does this mean to you? 2.How can you apply this to Chemistry? 3.How can you apply this to your plans for next year?

Chemical Formulas Chemistry II

Empirical vs. Molecular Molecular Formula – Actual # of atoms – Bond type: Covalent Glucose=C 6 H 12 O 6 Sucrose=C 12 H 24 O 12 Empirical Formula – Simplest ratio of atoms – Bond type: Ionic Glucose=CH 2 OSucrose=CH 2 O

Atomic Mass p + n – Average of isotopes Measured in amu (atoms) or g (moles)

Molecular Mass Sum of mass of molecule’s atoms – Based on molecular formula

Percent Composition Amount of an element in a molecule, by mass (# of atoms x mass) / molecular mass

WRAP UP If the empirical formula for a compound is CH 2 O and the molecular mass is 342 amu, what is the molecular formula? What molecule is this?