MOLES and ACCOUNTING 101

Balanced chemical equations give us proportions that can be used for predictions:

2 S + 3 O 2 à 2 SO 3

If 2 atoms of S are used, how many molecules of SO 3 can be made? ___2____

If 2 dozen atoms of S are used , how many dozen molecules of SO 3 can be made? __2__

If 6.02 X 10 23 atoms of S are used, how many molecules of SO 3 can be made? 6.02 X 10 23

What is the warm and fuzzy term we call 6.02 X 10 23 particles of anything? _MOLE__

If 1 mole of S atoms are used, how many moles of SO 3 molecules can be made? __1___

If 3 moles of O 2 atoms are used, how many moles of SO 3 molecules can be made? __2___

By using moles and the molar proportions found in a balanced chemical equation,

we can predict the amounts of chemicals in a reaction.

2 S + 3 O 2 à 2 SO 3

What is the molar proportions given in the equation above?

___ 2 __moles of S ___ 2 ___moles of SO 3 ___ 2 ___moles of SO 3

__ 3 __ moles O 2 __ 2 __ moles S __ 3 __ moles O 2

Conversion Examples:

A. Moles to Moles

If 0.25 moles of O 2 are used, how many moles of SO 3 can be produced?

__ .25 _ mole O 2 | 2 mole SO 3 = 0.17 moles SO 3

| 3 moles O 2

B. Grams to Moles

If 18 grams of S are used, how many moles of SO 3 can be produced?

__ 18 _ grams S | 1 mole S | 2 moles SO 3 = _.56__ moles SO 3

l 32 grams S | 2 moles S

C. Grams to Grams

If 65 grams of S are used, how many grams of SO 3 can be produced?

_ 65 __ grams S | 1 mole S | 2 moles SO 3 | ____ grams SO 3 = _162.5_ grams SO 3

| 32 grams S | 2 moles S | 1 mole SO 3

D. Moles to Liters

If 2.5 moles of S are used, how many liters of a gaseous SO 3 can be produced?

_ 2.5 __moles S | 2 mole SO 3 | _ 22.4 liters SO 3 = __207.2__ liters SO 3

| 2 moles S | 1 mole SO 3

E. Grams to Liters

If 5.6 grams of S are used, how many liters of SO 3 can be produced?

_ 5.6 grams S | 2 mole SO 3 | _ 22.4 liters SO 3 = __ 125.44 __ liters SO 3

| 2 moles S | 1 mole SO 3

F. Liters to Liters

If 12 liters of O 2 are used, how many liters of SO 3 can be produced?

__ 12 _ liters O 2 | 1 mole O 2 | 2 moles SO 3 | 22.4 liters SO 3 = __8__ liters SO 3

| 22.4 liters O 2 | 3 moles O 2 | 1 mole SO 3