Mole

StoichiometryThe study of quantitative relationships between the

amounts of reactants used and products formed by a chemical reactions; it is based on the law

of conservation of mass.

MoleThe SI base unit used to

measure the amount of a substance.

Avogadro’s NumberThe number of representative particles in a mole, and can be

rounded to three significant digits:

6.02 X 1023 molecules/mol

moles/L =M

Molarity

Molecule Forms when two or

more atoms covalently bond.

To find the number of molecules it takes to equal a

certain number of moles. Take the number of moles given and

multiply by Avogadro’s number.

How many molecules of Sucrose is in 3.50 moles of Sucrose.

3.50 mol Sucrose X 6.02x1023 molecules/mol =2.11x1024molecules of Sucrose

How many molecules of Sodium Hydroxide is in 4.80 moles of

Sodium Hydroxide?4.80 mol Sodium Hydroxide X

6.02x1023molecules/mol

=2.89x1024 molecules of Sodium Hydroxide

To find the number of moles it takes to equal a certain

number of molecules. Take the number of molecules given and divide by Avogadro’s number.

How many moles of Sucrose is in 3.54x1024 molecules of

Sucrose.

3.54x1024 molecules of Sucrose ÷

6.02x1023 molecules/mol

=5.88 moles of Sucrose

How many moles of Sodium Hydroxide is in 5.63x1024

molecules of Sodium Hydroxide.

5.63x1024 molecules NaOH ÷6.02x1023 molecules/mol=9.35 moles of NaOH

Molar MassThe mass in grams of one mole of any pure

substance.g/mol

To find the number of grams of substance. Take the number of

moles given and multiply by the substance’s molar mass.

Find the mass of 3.2 moles of Butane needed to complete the

reaction.

3.2 mol of Butane X

58.14 g/mol

=186.05 g of Butane

Find the mass of 4.5 moles of Pentanol needed to complete

the reaction.

4.5 mol Pentanol X86.15 g/mol=387.68 g of Pentanol

To find the number of moles of substance. Take the number of grams given and divide by the

substance’s molar mass.

Find the moles of 23 g of water needed to complete the

reaction.

23 g water ÷18.02 g/mol=1.28 mol of water

Find the moles of 112 g of Hydrochloric Acid needed to

complete the reaction.

112 g of Hydrochloric Acid ÷36.46 g/mol=3.07 mol of Hydrochloric Acid

To find the number of moles of an element in a compound,

multiply the moles of the compound with the ratio of

number of elements to 1 mol of compound.

How many moles of Fluorine is found in 5.50 moles of Freon

(CCl2F2).

5.50 mol CCl2F2 X

2 mol F atoms/1 mol CCl2F2 = 11.0 mol F atoms

How many moles of Oxygen is found in 4.75 moles of Glucose

(C6H12O6).

4.75 mol C6H12O6 X 6 mol O atoms/1 mol C6H12O6 = 28.5 mol O atoms

To find the moles of a compound, take the mass of the compound and divide by

the molar mass of the compound.

How many moles are there of 47g of water?

47g of water ÷

18.02 g/mol of water

= 2.61 mol of water

How many moles are there of 21g of Benzene?

21g of Benzene ÷

78.12 g/mol of Benzene

= 0.27 mol of Benzene

Mole Ratio

In a balanced equation, the ration between the

numbers of moles of any two substances.

To find mole ratio, put moles of one substance over the moles of another substance in chemical

equation.2KClO3 → 2KCl + 3O2

2mol KClO3/2mol KCl

2 mol KClO3/3mol O2