Balancing Chemical Equations

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Balancing equations is a necessary skill in chemistry and it reflects the fact that matter is neither created nor destroyed, according to the law of conservation of mass (Thank you Antoine Laurent Lavoisier). Simply put, the number atoms before and after reaction does not change. Atoms are not lost.

 

Antoine Laurent Lavoisier showed that although matter changes its state, its quantity remains constant throughout a chemical reaction. He was a French chemist, born in Paris, and considered the founder of modern chemistry. (1743-1794).

 

Consider the following reaction where water is broken down into oxygen gas and hydrogen gas:

 

Water

Oxygen Gas

+

Hydrogen Gas

H20

 

02

+

H2

 

The formula for each molecule above is correct. However, as you can see, it seems that we have gained an extra oxygen atom. This is not possible. Something is wrong.

 

 

Balancing this equation will satisfy the law of conservation of mass. See the solution below:

 

Water

Oxygen Gas

+

Hydrogen Gas

2H20

 

02

+

2H2

 

Write a 2 before the water molecule. 2 water molecules can result in 1 oxygen gas molecule after reaction. As you can see, the number of oxygen atoms is the same before and after reaction.

 

Lastly, if we write a 2 before the hydrogen gas molecule, we will have balanced the number of hydrogen atoms before and after reaction. The total number of atoms is the same before and after reaction.

 

Practice balancing equations: Balancing Chemical Equations Simulation

 

More Practice balancing equations: Balancing Chemical Equations Rags to Riches Game

 

Even More Practice: http://funbasedlearning.com/chemistry/chembalancer/default.htm

 

 

Another Conservation of Mass Link: Conservation of Mass

 

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