Law of conservation of mass

Front

What is the Law of Conservation of Mass?

Back

Mass is never created or destroyed in a chemical reaction.

Front

If a chemical reaction starts with 20g of reactants, what should the total mass of products be?

Back

20g of products.

Front

When balancing the equation P4 + O2 --> P2O3, what are the coefficients?

Back

1, 3, 2.

Front

What happens to the mass of reactants and products in a chemical reaction?

Back

They both weigh the same.

Front

What evidence shows that the number of atoms before and after a reaction is equal?

Back

The mass of the reactants equals the mass of the products.

Front

What is a reactant?

Back

A substance that undergoes a chemical change in a reaction.

Front

What is a product?

Back

A substance that is formed as a result of a chemical reaction.

Front

What does it mean to balance a chemical equation?

Back

To ensure that the number of atoms for each element is the same on both sides of the equation.

Front

Why is it important to balance chemical equations?

Back

To comply with the Law of Conservation of Mass.

Front

What is an example of a physical change?

Back

Melting ice.