MOLES and ACCOUNTING 101

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

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** 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: **

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** 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

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

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

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

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