Chemical Changes

Which of the following is a sign that a chemical reaction has occurred?

• change in shape
• melting
• formation of a gas
• dissolving

Tags

NGSS.MS-PS1-2

what is the definition of chemical change?

• any change that results in the formation of new chemical substances. 
• changing clothes
• matter cannot be created or destroyed, only change form
• changes affecting the form of a chemical substance, but not its chemical composition.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

The formula below represents the most common carbohydrate known as glucose. Which information can be determined from the chemical formula?
C₆H₁₂O₆

• The structural arrangement of the atoms in a glucose molecule
• The color of a glucose molecule
• The size of a glucose molecule
• The number of atoms of each element in a glucose molecule

Tags

NGSS.MS-PS1-1

The reactants are on the left side of the chemical equation.

• True
• False

Tags

NGSS.MS-PS1-5

Two clear colorless solutions were combined.
The student observed that the temperature changed from 25 •C to 23 •C when the solutions were combined and that a white substance rapidly formed and settled to the bottom of the container. What most likely happened to produce these results?

• One of the original compounds came out of solution
• The solutions reacted chemically
• Some of the water froze into ice crystals
• Rapid evaporation of water occurred, leaving a solid

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

How many atoms in all are in a molecule of serotonin?

C₁₀H₁₂N₂O

• 22
• 24
• 25
• 4

Tags

NGSS.MS-PS1-1

All of the following reactions are correctly balanced except-

• A
• B
• C
• D

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-5

Which of these is NOT a sign that a chemical change has occurred?

• A loss of transparency

• An unexpected color change

• A temperature change

• The formation of a precipitate

Tags

NGSS.MS-PS1-2

The Law of Conservation of Mass states

• that matter exists in all states and reacts the same

• that matter can only be changed into new substances by introducing a catalyst

• that matter exists in the same state throughout any chemical change

• that matter cannot be created or destroyed and that the mass of the products must equal the mass of the reactants

Tags

NGSS.MS-PS1-5

How many Al atoms are in this compound? 4Al₂O₃

• 2

• 8

• 6

• 4

Tags

NGSS.MS-PS1-1