Stoichiometry

Mole Map

Mole Island

Particle Peninsula

Liter Lake

Mass Mountain

Using the Mole Map with Chemical Equations

• We can convert between Moles, Particles and Grams, but…

• This only gives us information about one substance!

• How do we determine how much reactants to use in a chemical reaction? Or how much product we will create?

STOICHIOMETRY

Proportional Relationships

I have 5 eggs. How many cookies can I make?

3/4 c. brown sugar1 tsp vanilla extract2 eggs2 c. chocolate chipsMakes 5 dozen cookies.

2 1/4 c. flour1 tsp. baking soda1 tsp. salt1 c. butter3/4 c. sugar

5 eggs 5 doz.

2 eggs= 12.5 dozen cookies

Ratio of eggs to cookies

Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

150 cookies

Mole Ratio

• A conversion factor that converts moles of one compound in a balanced chemical equation into moles of another compound.

2 H2 + O2 2 H2O

• Coefficients tell how many particles (or MOLES of particles) of each chemical is needed in the reaction.

Mole Ratios

How many moles of water will be formed if I react 14.0 moles of oxygen with excess H2?

2 H2 + O2 2 H2O

14.0 moles O2 x 2 moles H2O = 28.0 moles H2O 1 mole O2

MOLE RATIOFrom the balanced equation.

Coefficients tell moles of each substance.

Mole Island

Stoichiometry Sea Known UnknownSubstance A Substance B

Mass Mountain

Liter Lake

Particle Peninsula

Mole Island

Mass Mountain

Liter Lake

Particle Peninsula

Mole RatioRaft

1 mole = 6.022 x 10 23 particles

(atoms or molecules)

Mass

Particles

Mole Mole

Mass

Particles

Known

Substance A1 mole = molar mass (g)

Use coefficientsfrom balanced

chemical equation

1 mole =

6.022 x

1023 partic

les

(atoms or m

olecules)

1 mole =

molar m

ass (g

)

Unknown

Substance B

Volume1 mole = 22.4 L @ STP

Volume1 mole = 22.4 L @ STP

Stoichiometry Steps1. Write a balanced equation.2. Identify known & unknown.3. Line up conversion factors.

– Mole ratio - moles moles– Molar mass - moles grams

Core step in all stoichiometry problems!!

– Mole ratio - moles moles

4. Check answer.

Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

How many moles of KClO3 must decompose in order to produce 9 moles of oxygen gas?

2KClO3 2KCl + 3O2 ? mol 9 mol

Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

O2 KClO3

x mol KClO3 = 9 mol O2 = 6 mol KClO3

2 mol KClO3

3 mol O26 mol

Stoichiometry

2 TiO2 + 4 Cl2 + 3 C CO2 + 2 CO + 2 TiCl4

4.55 molx mol

C Cl2

x mol Cl2 = 4.55 mol C3 mol C

= 6.07 mol Cl24 mol Cl2

C TiO2

x molecules TiCl4 = 115 g TiO2 80 g TiO2

= 8.66x1023 molecules TiCl4

1 mol TiO2 2 mol TiCl42 mol TiO2

6.02x1023 molecules TiCl41 mol TiCl4

x g TiO2 = 4.55 mol C3 mol C

= 243 g TiO2

2 mol TiO2 80 g TiO2

1 mol TiO2

How many moles of chlorine will react with 4.55 moles of carbon?

How many grams of titanium (IV) oxide will react with 4.55 moles of carbon?

x g

How many molecules of TiCl4 will react with 115 g TiO2?

TiO2 TiCl4

x molecules115 g