Understanding Matter and Conservation of Mass | Grade 4

What happens to the water in the glass as time passes?

• It disappears completely.

• It changes color.

• It turns into ice.

• It evaporates into the air.

What happens during a physical change in matter?

• A change that can usually be undone.

• A change that forms a new substance.

• A change that increases mass.

• A change that involves a chemical reaction.

Which of these is a chemical change (when something changes into a new substance)?

• Boiling water.

• Baking a cake.

• Melting ice.

• Dissolving sugar in water.

What are the substances called that change during a chemical reaction (when materials mix and make something new)?

• Reactants

• Products

• Elements

• Catalysts

What happens when a chemical reaction takes place?

• The mass is lost.

• A new substance is produced.

• The reactants remain unchanged.

• A new element is formed.

What can show you that a chemical change is happening?

• The substance freezes.

• The substance melts.

• Gas bubbles are produced.

• The substance changes color.

What does the conservation of mass (idea that matter cannot disappear) tell us?

• Mass is neither created nor destroyed.

• Mass is only lost during chemical reactions.

• Mass can change into energy.

• Mass can be created and destroyed.

What happens to water molecules when water evaporates (turns from liquid to gas)?

• They turn into ice.

• They become part of the air.

• They disappear.

• They change into sugar.

When sugar dissolves in water, what happens to its mass (how much matter it has)?

• It increases.

• It decreases.

• It remains the same.

• It becomes zero.

How can you show that the total mass stays the same when sugar dissolves in water?

• By tasting the solution.

• By measuring the mass before and after dissolving.

• By heating the solution.

• By observing the color change.