Science on the Main Stage Lesson 2 Quiz

What is the Law of Conservation of Mass?

• Mass is created in a chemical reaction

• Mass is created in a physical change

• New chemicals formed from a chemical reaction have a larger overall mass than the original reactants

• Mass is never created or destroyed

Which statement best describes how Makayla knows there was a chemical reaction?

• Makayla knows a chemical reaction has taken place because the sodium changed state.

• Makayla knows a chemical reaction has taken place because the sodium dissolved.

• Makayla knows a chemical reaction has taken place because the sodium fizzed.

• Makayla knows a chemical reaction has taken place because the sodium disappeared.

What is the main difference between a physical and a chemical change?

• Physical changes are reversible, chemical changes are not.

• Chemical changes involve a change in state, physical changes do not.

• Physical changes create new substances, chemical changes do not.

• Chemical changes are always visible, physical changes are not.

In reaction A +B --> C, reactants A + B have a total mass of 9g. What is the mass of product C?

• 4g

• 5g

• 9g

• 14g

• 2

• 3

• 4

• 8

Which of these shows the reaction that Luis carried out between potassium and hydrochloric acid?

• Reaction A

• Reaction B

• Reaction C

• Reaction D

Is this equation balanced?

• Yes

• No

In the equation shown, what are the product(s)?

• N₂ + H₂

• NH₃

• 2

• 3

• 5

• 6

How many neutrons can be found in an atom of Na (Sodium)?

• 12

• 11

• 22.99

• 23