Molar Relationships

Molar RelationshipsA balanced chemical equation can be interpreted in numbers of molecules, but generally chemists interpret equations as “mole-to-mole” relationships.2H2(g) + O2(g) → 2H2O(l)In the equation above: 2 moles of hydrogen gas and 1 mole of oxygen gas produce 2 moles of liquid water.

Therefore:H2 & O2 have a 2:1 mole-to-mole ratioO2 & H2O have a 1:2 mole-to-mole ratioH2 & H2O have a 1:1 mole-to-mole ratio

2H2(g) + O2(g) → 2H2O(l)

Molar Relationships

What are the mole-to-mole ratios in the chemical equation above?

N2 + 3H2 → 2NH3

Molar Relationships

Find the number of moles of NH3 that can be formed from 4.8 mol H2 using the balanced reaction below.

N2 + 3H2 → 2NH3

Molar Relationships

4.8 mol H2

2 mol NH3

3 mol H2

x = 3.2 mol NH3

Find the number of moles of LiNO3 needed to produce 3.2 mol Pb(NO3)4 using the balanced reaction below.

Pb(SO4)2 + 4LiNO3 Pb(NO3)4 + 2Li2SO4

Molar Relationships

3.2 mol Pb(NO3)

4

4 mol LiNO3

1 mol Pb(NO3)4

x = 12.8 mol LiNO3

PracticeProblems

Grab your clicker!(& a calculator)

Consider the balanced chemical reaction:

2Fe + 3 H2S04 → Fe2(SO4)3 + 3H2

How many moles of Fe are required to produce 9 moles of H2?A. 9 molesB. 2 molesC. 4.5 molesD. 6 moles

Question #1

Consider the balanced chemical reaction:2Fe + 3 H2S04 → Fe2(SO4)3 + 3H2

How many moles of Fe2(SO4)3 will be produced if we begin with 17 moles of Fe?A. 17 molesB. 8.5 molesC. 34 molesD. 11 moles

Question #2

Consider the balanced chemical reaction:

2C2H6 + 7O2 → 6H2O + 4CO2

How many moles of carbon dioxide are produced from 1 mole of C2H6?A. 1 molesB. 2 molesC. 7 molesD. 8 moles

Question #3

Consider the balanced chemical reaction:

2C2H6 + 7O2 → 6H2O + 4CO2

How many moles of O2 are required to produce 9 moles of H2O?A. 10.5 molesB. 6 molesC. 9 molesD. 7.5 moles

Question #4

Consider the following chemical reaction:

KOH + H3PO4→ K3PO4 + H2OHow many moles of KOH are required to produce 12.5 moles of H2O?A. 2.5 molesB. 7.5 molesC. 9 molesD. 12.5 moles

Question #5

Consider the following chemical reaction:

KOH + H3PO4→ K3PO4 + H2OHow many moles of H3PO4 are required to produce 9 moles of H2O?A. 3 molesB. 6 molesC. 9 molesD. 7 moles

Question #6