Conservation of Mass

Conservation of Mass

Chemical reactions

• In a chemical reaction, reactants rearrange to form products

• The ingredients to make a sandwich are the reactants, the sandwich is the product.

Mass is conserved

• Mass (how much stuff) stays the same before and after a chemical reaction.

• If you were to count the atoms before a reaction, it would be the same as after.

Multiple Choice

In this reaction hydrogen and oxygen gas react to form water. How many atoms of oxygen are there before and after the reaction?

• 1

• 2

• 3

• 4

Equations must be balanced

• When writing chemical equations, we must write them in a way that follows conservation of mass

• In today's activity, we will see how we can add coefficients to make these equations balanced