Semester Review

Complete the following statement by deciding if the descriptions represent a physical or a chemical change. Chewing food describes a _________, while digesting food describes a _________

• Chewing food describes a physical change, while digesting food describes a chemical change.

• Chewing food describes a chemical change, while digesting food describes a physical change.

• Chewing food describes a chemical change, while digesting food describes a chemical change.

• Chewing food describes a physical change, while digesting food describes a physical change.

Tags

NGSS.MS-PS1-2

What evidence indicates that a chemical change has taken place? Pair the description of a chemical reaction with the type of evidence that is being observed. Match the descriptions to the correct type of evidence.

• change in color

• formation of a precipitate (solid)

• formation of a gas

• formation of a gas

• change in temperature

• change in temperature

• formation of a precipitate (solid)

• change in color

Tags

NGSS.MS-PS1-2

What evidence indicates that a chemical change has taken place? Match the description of what the student is seeing during the reaction to the actual change that is taking place. Move the answers to the correct boxes.

• production of an odor

• change in temperature

• light is produced

• light is produced

• change in temperature

• production of an odor

• something is burning

• something is burning

Tags

NGSS.MS-PS1-2

How can physical vs. chemical changes be differentiated? Indicate whether the following examples represent physical or chemical changes. Shattering glass:

• physical change

• chemical change

How can physical vs. chemical changes be differentiated? Indicate whether the following examples represent physical or chemical changes. Select the correct answer. Moldy bread:

• physical change

• chemical change

Tags

NGSS.MS-PS1-2

How can physical vs. chemical changes be differentiated? Indicate whether the following examples represent physical or chemical changes. Slicing raw meat:

• physical change

• chemical change

How can physical vs. chemical changes be differentiated? Indicate whether the following examples represent physical or chemical changes. Steam condensing on the underside of a lid:

• physical change

• chemical change

Tags

NGSS.MS-PS1-4

Which of these activities involve a chemical reaction? Select TWO correct answers.

• Marshmallows are roasted over a campfire until they are browned.

• Raw onions are sliced up and eaten inside a cheeseburger.

• A student creates a volcano with mud, baking soda, and vinegar.

• Ice cream drips from the container as it is left out of the freezer by accident.

• The wall of the kitchen is freshly painted light yellow.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Pure sodium metal reacts violently with water to produce sodium hydroxide (NaOH). The reaction occurs very quickly and liberates a great deal of heat. Which of the following best describes why this reaction occurs so quickly and so violently?

• Sodium metal has only a single valence electron and has a very low electronegativity.

• Hydroxide ions have valence electrons in excess of a full octet.

• Hydroxide ions have very low electronegativity.

• The oxygen in the water reacts with the sodium metal to produce flammable oxygen gas.

Tags

NGSS.MS-PS1-1

When considering valence electrons, which group will gain electrons when ionic bonding?

• alkali metals

• transition metals

• halogens

• noble gases