Mole Concept and Mole Conversions

We have a score of items meaning 20. Then there is the dozen to mean 12 items. The mole identifies a very large number of items. The mole is a unit that is defined as 6.023 X 10²³ particles. It is also equal to the formula mass of a substance expressed in grams. For example:

1 mole of H₂O = 6.023 X 10²³ molecules of H₂O = 18 grams H₂O

This statement establishes the relationship between mole units and molecule units and the relationship between mole units and gram units.

      

Mole to gram conversion

Determine the number of grams in 4 moles of H₂O

Formula mass H₂O = (2 x 1.0) + (1 x 16) = 18

1 mole H₂O = formula mass H₂O = 18 grams H₂O

4 moles H₂O x 18 grams / 1 mole = 72 grams H₂O

 

Gram to Mole conversion

Determine the number of moles in 88 grams of CO₂

Formula Mass CO₂ = (1 x 12) + (2 x 16) = 44

1 mole of CO₂ = formula mass CO₂ = 44 grams CO₂

88 grams CO₂ x 1 mole CO₂ / 44 grams CO₂ = 2 moles CO₂

 

Mole to molecule conversion

Determine the number of molecules of H₂O in 3 moles H₂O

1 mole H₂O = 6.023 X 10²³ molecules H₂O

3 moles H₂O x 6.023 X 10²³ molecules H₂O / 1 mole H₂O = 18.069 X 10²³ molecules H₂O = 1.8069 X 10²⁴ molecules H2O

Mole to Atoms Conversion

How many atoms are present in 17.0 mol of water?

In order to convert mols of a substance to atoms one must first convert mols to molecules

step 1. mols ----> molecules

The relationship between mols and molecules is:

1 mol of any substance = 6.023 X 10²³ molecules of that substance.

17.0 moles H₂O X 6.023 X 10²³ / 1 mole H₂O = 102.4 X 10²³ = 1.02 X 10²⁵ molecules H₂O

step 2. molecules of substance ----> total atoms

That would depend upon the formula of the substance which in this case is H₂O

The subscripts that appear right after the symbol representing an element can be interpreted as atoms of that element in one molecule of the substance.

According to the formula for H₂O:

1 molecule H₂O = 2 atoms H + 1 atom O = 3 atoms total

So once you have determined the number of molecules of H₂O from step 1 you then can use the above relationship between molecules and total atoms to determine the total atoms in the number of molecules determined in step 1

1.02 X 10²³ molecules H₂O X 3 atoms / 1 molecule H₂O = 3.06 X 10²³ atoms total

Given 5 moles of Sulfuric Acid having a formula of H2SO4 answer the following questions:

How many grams of Sulfuric Acid would this be?

Formula Mass H2SO4 = 2(1.0)+ 1(32)+ 4(16) = 98

1 mole H2SO4 = Formula Mass H2SO4 in grams = 98 grams H2SO4

5 moles H2SO4 X 98 grams / 1 mole = 490 grams
 
How many molecules of Sulfuric Acid would that be?

1 mole H2SO4 = 6.023 X 1023 molecules H2SO4

5 moles H2SO4 X 6.023 X 1023 molecules / 1 mole = 30.1 X 1023 = 3.01 X 1024 molecules H2SO4
 
How many Hydrogen atoms would be in this amount of Sulfuric Acid?

In H2SO4 there is:

2 atoms H = 1 molecule H2SO4

3.01 X 1024 molecules H2SO4 X 2 atoms H / 1 molecule H2SO4 = 6.02 X 1024 atoms H
 
How many Oxygen atoms would there be in this much Sulfuric Acid?

In H2SO4 there is:

4 atoms O = 1 molecule H2SO4

3.01 X 1024 molecules H2SO4 X 4 atoms O / 1 molecule H2SO4 = 12.04 X 1024 = 1.204 X 1025 atoms O

HOPE THIS HELPS YOU !!!!!