Avogadro’s Number

6.02 X 1023

1 Mole of anything

6.02 X 1023 of that thing

Can be:

- atoms- molecules- ions

Particles

0.5 Mole

3.01 X 1023

0.25 Mole

1.50 X 1023

2.0 Mole

12.04 X 1023

Or1.204 X 1024

1.0 Mole of any gas at STP

22.4 Liters

STP

Standard Temperature = 0CStandard 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 H2O

2 X H = 2 X 1.0 = 2.01 X O = 1 X 16.0 = 16.0

Sum = 18.0 amu’s

Formula Mass of NH3

3 X H = 3 X 1.0 = 3.01 X N = 1 X 14.0 = 14.0

Sum = 17.0 amu

Formula Mass of CO2

1 X C = 1 X 12.0 = 12.02 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

H2O = NH3 =CO2 =

18.0 grams17.0 grams44.0 grams

Count up the atoms in (NH4)2SO4

For Paren: SubInside X Suboutside

N: 2 S: 1H: 8 O: 4

Count up the atoms in 2Mg3(PO4)2

For Paren: SubInside X Suboutside

Coefficients X subs in formula

Mg: 6 P: 4 O: 16

The “2” applies to every element in the formula.

# of Moles

# of Grams

# ofParticles

# ofLiters (gas)

X 6.02 X 1023

X Formula Mass

X 22.4 L/mole by 6.02 X 1023

byformula mass

by22.4

Percent

Part X 100% Whole

Percent H in H2O

Part X 100% = 2 X 100%

Whole 18

Percent O in H2O

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 (SiO2, SiC, Cdia, Cgraph)

Types of covalent substances

Ionic Compound

Formula contains metal plus nonmetal

Hydrate

Ionic compound that has H2O molecules incorporated into

its structure.

Anhydrate

Substance that remains after the water is removed from a

hydrate.

CuSO4•5H2O

Formula of a hydrated salt. • means “is associated with.”H2O molecules are stuffed in

the empty spaces.

CuSO4·5H2O ?

CuSO4 + 5H2O

Heat to constant mass

Evaporates into airanhydrate

hydrate

Formula mass of CuSO4•5H2O

Mass of CuSO4 plus mass of 5 water molecules.

249.6 grams/mole

Percent H2O in CuSO4•5H2O

(from the formula)

Part X 100% = 90 X 100% Whole 249.6

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?

H2O H2O2 CH4 C2H6

C6H12O6 KCl P4O10 CaF2

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, 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 mass2) Divide formula mass/empirical

mass3) Multiply subscripts in empirical

formula by answer in step 2

Empirical formula = CH & Formula Mass = 78,

find Molecular Formula

1) Empirical mass = 132) Divide formula

mass/empirical mass = 78/13 = 6

3) Multiply subscripts: C6H6

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 H2O?

1)Mass of H2O = 12 – 8 = 4 g

2)Percent H2O = 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

O2

1 molecule of O2 or 1 mole of O2

2 atoms per molecule

O3

1 molecule of O3 or 1 mole of O3

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 45.23 g O2) 3.773 mol C, 9.50 mol H, and 2.827 mol

O3) Divide by 2.827: C1.33H3.36O1

4) Multiply by 3: C4H10O3