WHAT IS A MOLE?

Moles: Measuring Matter A UNIT OF MEASURE!!! 1 mole = 6.02 x representative particles – atoms, molecules, formula units, ions – Also called Avogadro's number

Moles 1 mole = 6.02 x particles molar mas 1 mole is also equal to the molar mass of a substance molar mass = atomic mass with the units g/mol *g/mol is the same as atomic mass except atomic mass has the units of amu Molar mass of compounds Molar mass of compounds – add up parts K 2 CrO 4 – Find the molar mass of K 2 CrO 4

Molar Mass

CHALK LAB!!

MAKE FLIP CHART: 4 SHEETS

Mole Conversions particles to moles particles to moles # particles 1 mole 6.02 x particles moles to particles moles to particles # moles 6.02 x particles 1 mole moles to mass (g) moles to mass (g) moles molar mass = 1 mole

Mole Conversions Mass (g) to moles Mass (g) to moles mass 1 mol = molar mass Mass (g) to particles Mass (g) to particles mass 1 mol 6.02 x particles molar mass 1 mol particles to mass (g) particles to mass (g) particles 1 mol molar mass 6.02 x particles 1 mol

MOLES to Particles Converting moles to particles – Conversion Factors # moles x 6.02 x particles 1 mol Convert 3.5 moles sucrose to molecules

Moles continued Converting particles to moles # particles x 1 mole = 6.02 x particles Calculate the # moles in 4.50 x atoms Zn Calculate the # moles in 4.50 x atoms Zn

Homework: 2/7 Do problems 1, 6, 7, 16, 17, & 20

Moles: Mass and the Mole Moles to mass: Moles to mass: # moles x # grams 1 mol – How many grams are in 3.00 mol Mn?

Moles: Mass and the Mole mass to moles: mass x 1 mol #grams – How many moles are in 525 g Ca?

Homework: 2/8 Do problems 8, 9, 12, 13 & 18

Moles -2: Mass and the Mole atoms to mass: # particles x 1 mol x # grams 6.02 x particles 1 mol – How much mass is in 5.50 x atoms of helium?

mass to atoms: mass x 1 molx 6.02 x atoms #grams1 mol – How many atoms of gold in 25.0 g?

Homework 2/9 Do problems: 10, 11, 14 & 15 QUIZ Tomorrow over mole conversions!!

Moles: Moles of Compounds Can find moles of a part of a compound – How many moles of F are in 5.50 moles CCl 2 F 2 ? * Get ratio from formula. – Determine the number of moles of Al ions in 1.25 mol Al 2 O 3

Moles -4: Empirical and Molecular Formulas percent composition mass of element x 100 = % by mass mass of compound percent always adds up to 100 – Find % of H and O in water

Moles -4 continued Empirical formula – smallest whole # mole ratio of the elements * May or may not be actual molecular formula – To get: 1.Change g to mol 2.Get mole ratio 3.The ratios are the subscripts *If you are given % composition: assume % is grams Find the empirical formula of a sample with g S and g O.

Moles -4 continued Molecular formula – specific # of atoms of each element in compound experimentally determined molar mass = n mass of empirical formula multiply n by empirical formula subscripts molecular formula = (empirical formula) n Problem: The empirical formula of a substance is CH. The molecular mass of the compound is 78 amu. What is the molecular formula of the compound?

Moles 4 cont. – Chemical analysis indicates a sample is composed of 40.68% C, 5.08% H and 54.24% O and has a molar mass of g/mol. Determine the empirical and molecular formulas of succinic acid

Moles -5: The formula for a Hydrate Hydrate – compound with a specific # of water molecules bound to its atoms Naming: – name salt prefix hydrate CaCl 2 2H 2 O calcium chloride dihydrate – Prefixes are the same as those used for covalent compounds (see page 338 for review) Anhydrous – without water used to store water or as drying agents – Used to store solar energy i.e. sodium sulfate decahydrate