The Law of Conservation of Mass

Open Ended

How are the substances you started with (reactants) and the substances you ended with (products) related?

Open Ended

What does the arrow in a chemical equation mean?

Open Ended

When using the cubes to show a reaction 'occurred', did you observe any signs that completely new elements had appeared? Why or why not?

Open Ended

When you used cubes to model the reaction, what differences or changes did you observe?

Multiple Select

Based on your observations of the reaction between vinegar and baking soda, which of the following changes indicate a chemical reaction has occurred? (2 are correct)

• Change in shape

• Formation of gas bubbles

• Change in temperature (It got colder)

• Change in texture

Open Ended

What do you think happens to the matter when the bubbles form during the reaction between baking soda and vinegar?

Multiple Choice

Which statement best describes the law of conservation of mass?

• Matter can be created or destroyed.

• Matter can only change form, not be created or destroyed.

• The amount of mass is always different.

• Atoms disappear during chemical reactions.

Multiple Choice

Which of the following best describes the law of conservation of mass?

• Matter can be created or destroyed during a chemical reaction.

• The total mass of reactants equals the total mass of products in a chemical reaction.

• Mass is lost as energy during a chemical reaction.

• Only gases follow the law of conservation of mass.

Multiple Select

Which of the following are true about a balanced chemical equation? (There are 2 answers)

• It shows equal numbers of each type of atom on both sides.

• It proves the law of conservation of mass is followed.

• It always produces more mass in the products than the reactants.

• It is not necessary for chemical reactions.

Multiple Choice

Is this equation balanced?

• Balanced

• Unbalanced

Multiple Choice

Is this equation balanced? 3Mg + 2O₂ → 3MgO

• Balanced

• Unbalanced

Open Ended

Explain the difference between an open system and a closed system during a chemical reaction, and how this affects the mass in the end.

Open Ended

What is one real-life example where you have observed the law of conservation of mass in action?