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Difference between revisions of "Empirical Formula"

(→‎Finding the Empirical Formula)
(→‎Finding the Empirical Formula)
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{| class="wikitable"
 
{| class="wikitable"
 
| style="height:20px; width:200px; text-align:center;" |'''Number of Atoms'''
 
| style="height:20px; width:200px; text-align:center;" |'''Number of Atoms'''
−
| style="height:20px; width:200px; text-align:center;" |'''Picture'''
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| style="height:20px; width:200px; text-align:center;" |'''Skeletal Diagram'''
−
| style="height:20px; width:200px; text-align:center;" |'''Structural Diagram'''
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| style="height:20px; width:200px; text-align:center;" |'''Ball and Stick Model'''
 
|-
 
|-
 
| style="height:20px; width:200px; text-align:center;" |100 [[atom]]s of [[Hydrogen]] [[Chemical Reaction|react]] completely with 50 [[atom]]s of [[Oxygen]].
 
| style="height:20px; width:200px; text-align:center;" |100 [[atom]]s of [[Hydrogen]] [[Chemical Reaction|react]] completely with 50 [[atom]]s of [[Oxygen]].
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So the '''empirical formula''' is C<sub>2</sub>H<sub>5</sub>O
 
So the '''empirical formula''' is C<sub>2</sub>H<sub>5</sub>O
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|}
  
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{| class="wikitable"
 +
|-
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| style="height:20px; width:200px; text-align:center;" |64g of [[Oxygen]] is found to [[Chemical Reaction|react]] completely with 8g of [[Hydrogen]]. Find the '''empirical formula''' for the [[product]].
 +
| style="height:20px; width:200px; text-align:center;" |60g of [[Carbon]] is found to [[Chemical Reaction|react]] completely with 160g of [[Oxygen]]. Find the '''empirical formula''' for the [[product]].
 +
| style="height:20px; width:200px; text-align:center;" |416g of [[Sulphur]] is found to [[Chemical Reaction|react]] completely with [[Oxygen]] to produce 832g of [[product]]. Find the '''empirical formula''' for the [[product]].
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|-
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| style="height:20px; width:200px; text-align:left;" |
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[[Mass]] of [[Oxygen]] = 64g
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 +
[[Relative Atomic Mass]] of [[Oxygen]] = 16g
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[[Mole]]s of [[Oxygen]] = 64/16
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[[Mole]]s of [[Oxygen]] = 4 mole
 +
 +
[[Mass]] of [[Hydrogen]] = 8g
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 +
[[Relative Atomic Mass]] of [[Hydrogen]] = 1g
 +
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[[Mole]]s of [[Hydrogen]] = 8/1
 +
 +
[[Mole]]s of [[Hydrogen]] = 8 mole
 +
 +
[[Hydrogen]]:[[Oxygen]]
 +
 +
8:4
 +
 +
2:1
 +
 +
The '''empirical formula''' of the [[product]] is H<sub>2</sub>O
 +
 +
| style="height:20px; width:200px; text-align:left;" |
 +
[[Mass]] of [[Carbon]] = 60g
 +
 +
[[Relative Atomic Mass]] of [[Carbon]] = 12g
 +
 +
[[Mole]]s of [[Carbon]] = 60/12
 +
 +
[[Mole]]s of [[Carbon]] = 5 mole
 +
 +
[[Mass]] of [[Oxygen]] = 160g
 +
 +
[[Relative Atomic Mass]] of [[Oxygen]] = 16g
 +
 +
[[Mole]]s of [[Oxygen]] = 160/16
 +
 +
[[Mole]]s of [[Oxygen]] = 10 mole
 +
 +
[[Carbon]]:[[Oxygen]]
 +
 +
5:10
 +
 +
1:2
 +
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The '''empirical formula''' of the [[product]] is CO<sub>2</sub>
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 +
| style="height:20px; width:200px; text-align:left;" |Text
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[[Mass]] of [[Sulphur]] = 416g
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 +
[[Relative Atomic Mass]] of [[Sulphur]] = 32g
 +
 +
[[Mole]]s of [[Sulphur]] = 416/32
 +
 +
[[Mole]]s of [[Sulphur]] = 32 mole
 +
 +
[[Mass]] of [[Oxygen]] = 416g
 +
 +
[[Relative Atomic Mass]] of [[Oxygen]] = 16g
 +
 +
[[Mole]]s of [[Oxygen]] = 416/16
 +
 +
[[Mole]]s of [[Oxygen]] = 26 mole
 +
 +
[[Sulphur]]:[[Oxygen]]
 +
 +
13:26
 +
 +
1:2
 +
 +
The '''empirical formula''' of the [[product]] is SO<sub>2</sub>
  
 
|}
 
|}

Revision as of 16:43, 2 January 2019

Key Stage 4

Meaning

An empirical formula is the simplest ratio of the different types of atom in a compound.

About Empirical Formulae

The empirical formula of a compound may not be the same as the chemical formula:

Empirical formulae are calculated from the amount of atoms in a chemical reaction.
The number of atoms can be found if you know the mass of different elements and the relative atomic mass of the elements in the reaction.

Finding the Empirical Formula

Number of Atoms Skeletal Diagram Ball and Stick Model
100 atoms of Hydrogen react completely with 50 atoms of Oxygen.
SkeletalFormulaButane.png
BallandStickButan12diol.png

The ratio of Hydrogen atoms to Oxygen atoms

H:O

100:50

2:1

So the empirical formula is H2O

In this diagram there are 4 Carbon atoms, 10 Hydrogen atoms.

The ratio of atoms is:

C:H

4:10

2:5

So the empirical formula is C2H5

In this diagram there are 4 Carbon atoms, 10 Hydrogen atoms and 2 Oxygen atoms.

The ratio of atoms is:

C:H:O

4:10:2

2:5:1

So the empirical formula is C2H5O

64g of Oxygen is found to react completely with 8g of Hydrogen. Find the empirical formula for the product. 60g of Carbon is found to react completely with 160g of Oxygen. Find the empirical formula for the product. 416g of Sulphur is found to react completely with Oxygen to produce 832g of product. Find the empirical formula for the product.

Mass of Oxygen = 64g

Relative Atomic Mass of Oxygen = 16g

Moles of Oxygen = 64/16

Moles of Oxygen = 4 mole

Mass of Hydrogen = 8g

Relative Atomic Mass of Hydrogen = 1g

Moles of Hydrogen = 8/1

Moles of Hydrogen = 8 mole

Hydrogen:Oxygen

8:4

2:1

The empirical formula of the product is H2O

Mass of Carbon = 60g

Relative Atomic Mass of Carbon = 12g

Moles of Carbon = 60/12

Moles of Carbon = 5 mole

Mass of Oxygen = 160g

Relative Atomic Mass of Oxygen = 16g

Moles of Oxygen = 160/16

Moles of Oxygen = 10 mole

Carbon:Oxygen

5:10

1:2

The empirical formula of the product is CO2

Text

Mass of Sulphur = 416g

Relative Atomic Mass of Sulphur = 32g

Moles of Sulphur = 416/32

Moles of Sulphur = 32 mole

Mass of Oxygen = 416g

Relative Atomic Mass of Oxygen = 16g

Moles of Oxygen = 416/16

Moles of Oxygen = 26 mole

Sulphur:Oxygen

13:26

1:2

The empirical formula of the product is SO2

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