Law of Conservation of Mass

Front

What is the Law of Conservation of Mass?

Back

The Law of Conservation of Mass states that mass is neither created nor destroyed in a chemical reaction. The total mass of the reactants equals the total mass of the products.

Front

If 200 g of water freezes, what will be the mass of the frozen water?

Back

200 g

Front

What is a chemical reaction?

Back

A chemical reaction is a process that leads to the transformation of one set of chemical substances to another.

Front

Which of the following is not a chemical reaction: Burning of wood, Milk going bad, Mixing vinegar and baking soda, Melting of ice?

Back

Melting of ice.

Front

What does it mean for a chemical equation to be balanced?

Back

A chemical equation is balanced when both sides have the same number of atoms for each element.

Front

Identify a balanced chemical equation: CH₄ + O₂ → CO₂ + 2H₂O, H₂ + O₂ → 2H₂O₄, 4Al + 3O₂ → 2Al₂O₃.

Back

4Al + 3O₂ → 2Al₂O₃.

Front

What is the role of coefficients in a chemical equation?

Back

Coefficients indicate the number of molecules or moles of each substance involved in the reaction.

Front

What happens to the mass of substances during a chemical reaction?

Back

The total mass of the substances remains constant; it is conserved.

Front

What is an example of a physical change?

Back

Melting ice is an example of a physical change.

Front

What is an example of a chemical change?

Back

Burning wood is an example of a chemical change.