Avogadro’s Number 6.02 X 10 23

1 Mole of anything 6.02 X of that thing

Can be: - atoms - molecules - ions Particles

0.5 Mole 3.01 X 10 23

0.25 Mole 1.50 X 10 23

2.0 Mole X Or X 10 24

1.0 Mole of any gas at STP 22.4 Liters

STP Standard Temperature = 0  C Standard Pressure = 1 atm

0.5 mole of any gas 11.2 Liters

2.0 mole of any gas 44.8 Liters

3.0 mole of any gas 67.2 Liters

0.25 mole of any gas 5.6 Liters

Formula Mass Sum of the masses of the elements in the compound. Expressed in atomic mass units

Formula Mass of H 2 O 2 X H = 2 X 1.0 = X O = 1 X 16.0 = 16.0 Sum = 18.0 amu’s

Formula Mass of NH 3 3 X H = 3 X 1.0 = X N = 1 X 14.0 = 14.0 Sum = 17.0 amu

Formula Mass of CO 2 1 X C = 1 X 12.0 = X O = 2 X 16.0 = 32.0 Sum = 44.0 amu

Gram Formula Mass Formula mass expressed in grams. Equals the molar mass of the compound.

Molar Mass Mass of one mole of the substance.

Molar Mass H 2 O = NH 3 = CO 2 = 18.0 grams 17.0 grams 44.0 grams

Count up the atoms in (NH 4 ) 2 SO 4 For Paren: Sub Inside X Sub outside N: 2S: 1 H: 8O: 4

Count up the atoms in 2Mg 3 (PO 4 ) 2 For Paren: Sub Inside X Sub outside Coefficients X subs in formula Mg: 6P: 4O: 16 The “2” applies to every element in the formula.

# of Moles # of Grams # of Particles # of Liters (gas) X 6.02 X X Formula Mass X 22.4 L/mole  by 6.02 X  by formula mass  by 22.4

Percent Part X 100% Whole

Percent H in H 2 O Part X 100% = 2 X 100% Whole 18

Percent O in H 2 O Part X 100% = 16 X 100% Whole 18

Empirical Formula smallest whole number ratio of the elements in a compound

Molecular Formula Gives exact composition of molecule

Covalent Compound Formula contains all nonmetals

Molecular (vast majority) & Network (SiO 2, SiC, C dia, C graph ) Types of covalent substances

Ionic Compound Formula contains metal plus nonmetal

Hydrate Ionic compound that has H 2 O molecules incorporated into its structure.

Anhydrate Substance that remains after the water is removed from a hydrate.

CuSO 45H 2 O Formula of a hydrated salt. means “is associated with.” H 2 O molecules are stuffed in the empty spaces.

CuSO 4 ·5H 2 O  ? CuSO 4 + 5H 2 O  Heat to constant mass Evaporates into air anhydrate hydrate

Formula mass of CuSO 45H 2 O Mass of CuSO 4 plus mass of 5 water molecules grams/mole

Percent H 2 O in CuSO 4 5H 2 O (from the formula) Part X 100% = 90 X 100% Whole249.6

Metals All elements to the left of the staircase except H

Nonmetals All elements to the right of the staircase plus H

Binary Compound Compound made from 2 elements

Which formulas are empirical? H 2 OH 2 O 2 CH 4 C 2 H 6 C 6 H 12 O 6 KClP 4 O 10 CaF 2

Crystal Lattices Ionic Compounds, Metals, & Network Solids make….

Smallest repetitive unit in a crystal lattice Formula Unit

Have distinctly different properties than molecular substances. Substances with crystal lattices…

Types of Substances Ionic May be Binary Or may have > 2 elements May contain a transition metal Metallic Cu CuAl 2 Covalent May be Molecular or Network (SiO 2, SiC, C dia, C graph )

Ionic, Metallic, and Network solids What kind of substances have Crystal Lattices?

Empirical formulas only Substances that make crystal lattices have

Have both empirical & molecular formulas. The molecular formula is a whole- number multiple of the empirical formula. Molecular Covalent Substances

Given empirical formula & Formula Mass, find Molecular Formula 1)Find empirical mass 2)Divide formula mass/empirical mass 3)Multiply subscripts in empirical formula by answer in step 2

Empirical formula = CH & Formula Mass = 78, find Molecular Formula 1)Empirical mass = 13 2)Divide formula mass/empirical mass = 78/13 = 6 3)Multiply subscripts: C 6 H 6

12 grams of hydrated salt is heated to constant mass. After heating the mass is 8.0 grams. What is the percent salt & the percent H 2 O? 1)Mass of H 2 O = 12 – 8 = 4 g 2)Percent H 2 O = 4/12 X 100% 3)Percent salt = 8/12 X 100% Percent water in hydrate from experimental data.

He 1 atom of He or 1 mole of He 1 atom per molecule

O2O2 1 molecule of O 2 or 1 mole of O 2 2 atoms per molecule

O3O3 1 molecule of O 3 or 1 mole of O 3 3 atoms per molecule

Percent composition to empirical formula 1.Convert to mass. 2.Convert to moles. 3.Divide by small. 4.Multiply ‘til whole.

Find the empirical formula: 45.27% C, 9.50% H, 45.23% O 1)45.27 g C, 9.50 g H, and g O 2)3.773 mol C, 9.50 mol H, and mol O 3)Divide by 2.827: C 1.33 H 3.36 O 1 4)Multiply by 3: C 4 H 10 O 3