Law of Conversation of Matter

The Law of Conservation of Matter states that matter cannot be created nor destroyed, only transformed. This law applies to physical and chemical changes.

French chemist Antoine Lavoisier ( an·twaan la·vwuh·zay ) is most often credited with the discovery of the law of conservation of matter in the 1700’s. Through experimentation he was able to prove that total mass does not change during a chemical reaction.

He helped prove that matter wasn’t simply disappearing like it seems to do as something is burning, but was rather changing form into another substance of equal mass.

law of conservation
law conservation matter
 

The law applies during all physical changes. When this piggy bank breaks, you can measure the mass before and after and it will be the same.
As water evaporates, which is a phase change, the molecules remain the same but are just moving further apart and the mass remains the same.

 
 

This law is also why we balance chemical equations.

Let’s look at water and see the law of conservation of matter at work.

Notice you have four hydrogens and two oxygens on the left of the equation which we call the reactants and yields the same on the right side of the equation, which we call the products.

 
 

Let’s look at another example of the law of conversation.

The rusting of iron.
Again you have the same number of reactants and products.

 

So in summary, The law of conservation of matter states that matter cannot be created nor destroyed, but can be transformed. This law applies to all physical and chemical changes.