Chemical Reactions Review

In a laboratory, a sealed container with 100g of steam is cooled until all the steam becomes a liquid. The container is then cooled further until all the water becomes a solid. Which of the following remains constant during both of these changes?

• the mass of the water

• the pressure of the container

• the total energy of the water

• the position of the atoms in the container

Ms. Bristol measured the mass of a closed beaker containing several ice cubes. The mass was 100g. An hour later, after the ice cubes had melted, Ms. Bristol measured the mass of the beaker again. What was the mass of the beaker of water the second time?

• 50 g

• 75 g

• 100 g

• 150 g

According to the Law of Conservation of Mass,

• matter is always created in a chemical reaction

• matter is always destroyed in a chemical reaction

• matter is created and then destroyed in a chemical reaction

• matter is not created or destroyed in a chemical reaction

The diagram below shows a balance being used to measure a burning candle in a sealed glass ball before and after the burning is complete. As the candle burns, the size of the candle decreases, but the reading on the balance does not change. Which of the following is demonstrated by this experiment?

• The total mass of the system is constant.

• Energy is converted to mass when the candle is burned.

• Smoke particles have more mass than molecules of candle wax.

• Kinetic energy is converted to potential energy when the candle is burned.

Examine the following chemical reaction: H20 + CO2 → C6H12O6 + O2 What are the reactants?

• H20 + CO2

• →

• C6H12O6 + O2

• H20 + CO2 → C6H12O6 + O2

Examine the following chemical reaction: H20 + CO2 → C6H12O6 + O2 What are the products?

• H20 + CO2

• →

• C6H12O6 + O2

• H20 + CO2 → C6H12O6 + O2

Examine the following chemical reaction: H2O2 → H2O + O2 What are the products?

• H2O2

• →

• H2O + O2

• H2O2 → H2O + O2

Examine the following chemical reaction: H2O2 → H2O + O2 What are the reactants?

• H2O2

• →

• H2O + O2

• H2O2 → H2O + O2

Substances that start a chemical reaction are known as the

• reactants

• products

• chemicals

• substances

Substances created, or made, during a chemical reaction are known as the

• reactants

• products

• chemicals

• substances