Exploring Chemical Reactions and Conservation of Mass

What determines the physical and chemical properties of an element?

• The number of neutrons

• The number of protons and electrons

• The number of atoms

• The number of molecules

What are the new substances formed in a chemical reaction called?

• Reactants

• Elements

• Catalysts

• Products

Which of the following is NOT a sign of a chemical reaction?

• Change in shape

• Formation of a precipitate

• Change in temperature

• Production of light

Tags

NGSS.MS-PS1-2

What happens when a matchstick is lit?

• A physical change occurs

• A chemical reaction starts and light is produced

• The matchstick melts

• The matchstick absorbs energy

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

What is the purpose of a chemical equation?

• To identify the color change

• To measure the temperature change

• To describe the process of reactants changing into products

• To show the physical state of reactants

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-5

What does the law of conservation of mass state?

• Mass is always gained in a chemical reaction

• Mass is always lost in a chemical reaction

• The total mass of reactants is equal to the total mass of products

• Mass can be created or destroyed

Tags

NGSS.MS-PS1-5

What are coefficients used for in chemical equations?

• To show the color change

• To balance the chemical equation

• To show the physical state of substances

• To indicate the temperature change

Tags

NGSS.MS-PS1-5

In the formation of water, how many molecules of hydrogen react with one molecule of oxygen?

• One

• Two

• Three

• Four

Tags

NGSS.MS-PS1-5

What happens if a chemical equation is not balanced?

• The reactants will change

• The law of conservation of mass is violated

• The reaction will not occur

• The products will be different

Tags

NGSS.MS-PS1-5

Which of the following is a key concept learned in the video?

• Atoms do not rearrange in a chemical reaction

• Chemical reactions do not produce new substances

• The law of conservation of mass can be violated

• Chemical equations must always be balanced

Tags

NGSS.MS-PS1-5