2.7 Video Reactions & Conservation of Mass

What happens to atoms during a chemical reaction?

• They are destroyed and new atoms are created

• They rearrange and combine to form new substances

• They change into different types of atoms

• They remain unchanged and simply mix together

Which of the following is NOT a sign that a chemical reaction has occurred?

• Production of light

• Change in shape

• Change in color

• Formation of a precipitate

What do chemists use to describe the reactants and products of chemical reactions?

• Chemical Equations

• Molecular Models

What is the primary purpose of using coefficients in a chemical equation?

• To indicate the state of matter of reactants and products

• To balance the number of atoms on both sides of the equation

• To change the chemical properties of the substances

• To speed up the chemical reaction

According to the Law of Conservation of Mass, what must be true about the total mass in a chemical reaction?

• The total mass of reactants must be greater than the total mass of products

• The total mass of products must be greater than the total mass of reactants

• The total mass of reactants must equal the total mass of products in a balanced chemical equation

• The total mass can increase or decrease depending on the reaction