Chapter 10: The Mole

1 mole = 6.02 x 1023 particlesA mole is also called Avogadro’s number.

A paper clip is 3.2 cm in length. How many times can of mole of paper clips go around the Earth? (Circumference of the Earth is 25,000 miles, 1 in = 2.54 cm, 1 foot = 12 inches,1 mile = 5,280 feet)

6.02 x 10 23 particles – atoms, molecules, formula units

P. 287-290

Conversions: Moles Particles, Particles Moles P.290-291

# of moles x 6.02 x 10 23 particles = particles mole

# particles x mole = moles 6.02 x 10 23 particles

Freon - CCl2F2 study sample problem 10.3 on p. 292

How many Fluorine atoms are in 5.5 moles of Freon?

5.5 mol of CCl2F2 x 2 mol F Atoms = 11 mol of F atoms

1 mol of CCl2F2

The Mass of a Mole of an Element P. 293-294

Conversions: moles mass, mass moles

# of moles x # of grams = grams mole

grams x mole = moles# of grams

The Mass of a Mole of a Compound P. 295-296

What is the molar mass of Potassium Chromate?

The Mole to Mass Relationship P.297-298

1. Find the molar mass of the compound.

2. Convert moles to grams by using molar mass as a conversion factor.

Converting Moles to Mass - P. 298-299

Converting Mass to Moles of a Compound – P. 299

Particles Mass, Mass Particles

Move through the mole tunnel.

Mole (tunnel)

mass

Units (atoms, molecules)

6.02 x 1023

Molar Mass

Converting Mass to Particles

Calculating Percentage Composition P.305-307

% composition of an element = mass of element x 100% mass of compound

1. A compound is formed when 9.03 g of Mg combines with 3.48 g of N. What is the percent composition of the compound?

2. When a 14.2 g sample of mercury(II)oxide is decomposed into its elements by heating, 13.2 g of mercury is obtained. What is the percent composition of the compound?

3. Calculate the percentage composition of dicarbon hexahydride, sodium hydrogen sulfate and phosphoric acid.

Empirical Formula – The Simplest Formula P.309-310

• Convert % grams (Assume 100 g)• Convert grams moles• Divide each mole quantity by the smallest mole quantity• Can’t have decimals

• Convert grams moles

• Divide each mole quantity by the smallest mole quantity.

Determining Molecular FormulaA True Formula P.311-312

1.Determine the empirical formula.

2.Divide the molar mass by the molar mass of the empirical formula.

Hydrates

Opal – Silicon Dioxide an example of a hydrateWater is bonded to the atoms of the compound.

Desiccators

Removes water from the

surroundings.

Circuitry. Electronics and

optics.

Calcium Sulfate

Not soluble in alcoholCalcium Chloride

Naming Hydrates

• State the name of the substance and then add a prefix in front of the word hydrate

Ex. Na2CO3 * 10H2O – sodium carbonate decahydrate

Hydrated CoCl2

11.75 g before heating

Anhydrous CoCl2

w/o water

9.25 g after heating

Analyzing Hydrates

Analyzing Hydrates

• Find the mass of the water.• Determine the moles of the compound and

water. • Divide by the smallest mole ratio.