STOICHIOMETRY

STEPS

100

What is the first step you take when doing stoichiometry?

Write the balanced equation.

CONVERSIONS

100

What are you trying to find when you convert moles to moles?

The Mole Ratio.

300

Fe+O₂--->Fe₂O₃

Find the mole ratio of Iron to Oxygen

4:3

DEFINITIONS

100

What is Stoichiometry?

Mass relationships between substances in a chemical reaction.

MOLE ISLAND

100

When is 22.4 used?

When the gas is at stp.

200

How do we convert moles to grams?

Multiply by molar mass.

PROBLEMS

100

How many liters of NO2 are produced when 34 L O2 react with an excess of NO at STP? The balanced equation is

 2NO(g) + O2(g) → 2NO2(g).

34 L of O2 × 1 mol of O2 / 22.4 L of O2 = 1.51 mol of O2

1.51 mol of O2 × 2 mol of NO2 / 1 mol of O2 = 3.03 mol of NO2

3.03 mol of NO2 × 22.4 L / 1 mol of NO2 = 68 L

200

How many moles of O2 would you need to produce 25 mol H2O from the reaction of H2 &O2

2H2 + O2 -----------> 2H2O

25 mol H2O x 1 mol O2 / 2 mol H2O = 12.5 mol O2

300

How many moles of O2 would you need to produce 25 mol H2O from the reaction of H2 and O2?

2H2 + O2 → 2H2O

Given quantity × Mole ratio

Given quantity × wanted moles / Given moles

25 mol of H2O × 1 mole of O2 / 2 moles of H2O

12.5 moles of O2

400

How many moles of NH3 are produced when 0.60 mol of nitrogen react with hydrogen?

 N2 + 3H2 → 2NH3

0.60 moles of N2 × moles of NH3 / 1 mole of N2

1.2 mole of NH3