The mole

What is a MoleHow many socks come in a pair?

2How many eggs are in a dozen?

12How many eggs come in a gross?

144How many pencils come in a ream?

500

So how many things come in a mole?

Conversion ReviewDimensional Analysis

Example Problems

The Mole and Mass

Relative Mass

Molar Mass

Using molar mass

Converting between mass and atoms

Using the Mole with compounds

Chemical Formulas and the Mole

Molar Mass of a CompoundDetermine the molar mass of each of the

following compounds:NaOHCaCl2

KC2H3O2

C2H5OHHCNCCl4

(NH4)3PO4

Converting moles to massThe characteristic odor of garlic is due to the

compound (C3H5)2S. What is the mass of 2.5 moles of (C3H5)2S?

What is the mass of 3.25 mol of H2SO4?

Converting Mass to MolesCalculate the number of moles in 325 g of

Calcium hydroxide Ca(OH)2?

Calculate the number of moles in 22.6 g of AgNO3.

Mass to Number of Particles How many Aluminum Chloride molecules are

present in 35.6 g of AlCl3

How many Al atoms are there?

How many Cl atoms are there?

ExampleAluminum oxide (Al2O3) when dissolved in

water breaks apart into ions (Al3+ and O2-) how many moles of Al3+ will be produced when 1.5 moles of Al2O3 are dissolved in water?

Examples1. What is the molar mass of ethanol C2H5OH?

How many ethanol molecules are present in 45.6 g?How many carbon atoms are there in 45.6 g of ethanol?How many hydrogen atoms are there in 45.6 g of ethanol? How many oxygen atoms are there in 45.6 g of ethanol?

2. A sample of sodium sulfite Na2SO3 has a mass of 2.25 g How many molecules of sodium sulfite are there? How many atoms of sodium are there? How many atoms of Sulfur are there? How many atoms of oxygen are there?

Percent CompositionThe molar mass of NaOH is Na – 22.98 g/molO – 16 g/molH – 1 g/molTotal: 39.98 g/mol

ExampleNaHCO3

Empirical Formula

ExampleFind the empirical formula for hydrogen

peroxide which has a molar mass of 34 g/mol and is 5.9% Hydrogen and 94.1% Oxygen

Molecular Formula

Example

ExampleFind the empirical and molecular formula for

a compound that is 26.5% K, 35.4% Cr, and 38.1% O and has a molar mass of 294.2 g/mol.

ExampleFind the empirical and molecular formula for

a compound that is 26.7% carbon, 2.2% hydrogen, and 71.1% oxygen and has a molar mass of 90 g/mol.