Study the Mass of Catalysts During Reactions

Catalysts are substances that speed up chemical reactions. They're super helpful like that.

What's more, they're not changed during the course of the chemical reaction. They're not used up. They're not chemically changed. They come out exactly the same as they went in. 

This means that the mass of the catalyst stays the same too - the mass of the catalyst at the start of a chemical reaction is the same as the mass of the catalyst at the end of the reaction. 

Manganese dioxide is a catalyst that speeds up the breakdown of hydrogen peroxide. Hydrogen peroxide breaks down into water and oxygen. If 3 g of manganese dioxide is added to a beaker of hydrogen peroxide, you would be able to get 3 g of it back out once the hydrogen peroxide has been converted into oxygen and water. 

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