when a chemical change occurs, what do you know about the amount of matter in the new substances? what is this known as? (is it suppose to be a science question)

The law of conservation of mass states that the total mass of the products is equal to the total of the reactants.

A chemical change occurs because of a chemical reaction.

In a chemical reaction, the reactants are the starting substances and the products is the finishing substances. The amount of each type of atoms to start with and end with are also equal.

No matter disappears after a chemical reaction.

Answer:

The amount of matter in the new substances is the same as the original.

This is known as the law of conservation of mass.