Conservation of Mass (Matter) Test

A student is doing an experiment and has a container filled with 250 grams of ice. He closes the container with a lid and begins to heat it. At first, it melts to liquid water and then begins to boil after five more minutes. What happens to the water's mass during this time?

• Mass stays the same! The ice will go through a physical change but does not change chemically

• Mass will become less! Water vapor has less mass than ice.

• Mass will become greater! The lid is holding the gas in and gas moves at great motion.

According to the Law of Conservation of Mass, which box on the right correctly demonstrates the product of this reaction?

• Box A
• Box B
• Box C
• Box D

When a chemical reaction occurs, matter is neither created or destroyed. It only changes form. What is this called?

• Law of Mass and Matter
• Law of Conservation of Mass
• Balancing Equations
• Law of Conservation of Energy

In a popular demonstration, vinegar and baking soda are combined in a bottle as shown. Sodium carbonate, water, and carbon dioxide gas are formed. The balloon traps the carbon dioxide. If the bottle were left open with no balloon, predict which outcome is most likely.

• All substances would still be in the bottle.
• The surrounding air would have less carbon dioxide.
• The mass of the reactants would be less than the mass of the products. (baking soda and vinegar will be less than the gas formed)
• The mass of the products would be less than the mass of the reactants (gas formed will be less than the baking soda and vinegar because it will escape)

2H2O + 2Na → 2NaOH + H2 Which of these is a reactant in this chemical reaction?

• 2H2O
• 2NaOH
• H2
• 2NaOH + H2

2H2O + 2Na → 2NaOH + H2 Which of these is a product in this chemical reaction?

• H2
• 2Na
• 2H2O
• H2O

According to the Law of Conservation of Mass, what happens to the wood and oxygen when it is burned?

• The wood disappears.
• It chemically stays exactly the same
• The atoms in the wood and oxygen rearrange and form smoke and ash.
• Nothing

Explain how do reactants and products differ in a chemical reaction?

• Reactants are the substances that react together to form a new substance (product).

• products are the substances that react together to form a new substance (reactant).

• They are the same thing. Fancy words for matter and mass

What does the principle of conservation of mass mean?

• The reactants of a chemical equation should be more than the product
• The products of a chemical equation should be more than the reactants
• Matter is not created or destroyed

Look at the image. NaCl represents what in this equation?

• Product
• Reactant
• Mass
• Produce