Conservation of Mass (Crash Course)

What do you think happened to the water in the glass after being left out?

• It disappeared.

• It turned into gas and mixed with air.

• It changed into a solid.

• It stayed the same.

Tags

NGSS.MS-PS1-4

What kind of change occurs when sugar dissolves in water?

• Chemical change

• Physical change

• Both chemical and physical change

• No change occurs

Which of the following is a clue that a chemical change has taken place?

• The substance dissolves

• The mixture turns transparent

• The production of gas bubbles

• The substance can be separated easily

Tags

NGSS.MS-PS1-2

What is the difference between a physical change and a chemical change? Can both changes be reversed?

• Physical changes create new substances and are irreversible.
• Both physical and chemical changes are always reversible.
• Physical changes alter appearance without changing composition and are often reversible; chemical changes create new substances and are usually irreversible.
• Chemical changes alter appearance without changing composition and are often reversible.

In the sugar-water solution, what happens to the mass after the sugar dissolves?

• The mass of the solution is equal to the mass of the sugar and the water.

• The mass changes depending on the temperature of the solution.
• The mass increases after the sugar dissolves.
• The mass decreases after the sugar dissolves.

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

What is the conservation of mass?

• The conservation of mass is a fundamental principle stating that mass is neither created nor destroyed in chemical reactions.
• The conservation of mass applies only to gases.
• Mass is only conserved in physical changes.
• Mass can be created in chemical reactions.

Tags

NGSS.MS-PS1-5

A chemical reaction is...

• A physical change in which matter changes its form but not its chemical structure.

• A change where the mass of the substances is lost or gained after the process.

• The process in which two or more molecules interact to form one or more new substances.

• A process where molecules of substances break down into smaller parts without forming new substances.

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

In a chemical reaction, the (a)   are found before the arrow and the (b)   are found after the arrow.

• reactants
• products

Tags

NGSS.MS-PS1-5

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

• Mass can be created.

• Mass can be destroyed.

• Mass remains constant during physical and chemical changes.

• Mass only applies to solids.

Tags

NGSS.MS-PS1-5

Why is the law of conservation of mass important in understanding chemical reactions?

• It allows scientists to create new matter.

• It explains why atoms are lost in reactions.

• It proves that mass disappears during evaporation.

• It helps predict the amount of products in a reaction.

Tags

NGSS.MS-PS1-5