Unit 2 Review

The chemical formula for water is H₂O What does the formula show about each element in the

• The number of valence electrons

• The charge of the compound

• The mass of protons

• The number of atoms of each element

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NGSS.MS-PS1-1

Why are changes classified as chemical changes?

• New substances are formed

• Materials take different shapes

• Temperature affects the objects

• Some energy is absorbed

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NGSS.MS-PS1-2

NGSS.MS-PS1-5

Select all of the options that are compounds

• Neon (Ne)

• Ozone (O₃)

• Water (H₂O)

• Nitrogen (N₂)

• Ammonia (NH₃)

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NGSS.MS-PS1-1

Which action will cause sugar to form a new substance?

• Cooking sugar on the stove

• Pouring sugar through a screen

• Dissolving a sugar cube in water

• Crushing a sugar cube in pieces

Tags

NGSS.MS-PS1-2

In a classroom demonstration, a teacher pours sulfuric acid on some granulated sugar. The sugar turns yellow and then black. Smoke rises and a strong smell is released. What kind of change is this?

• Chemical

• Physical

• Magnetic

• Electric

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Choose all of the phrases that apply to every compound.

• Has a unique set of properties

• Is a solid at room temperature

• Made of two or more elements

• Made of chemically joined atoms

• Can be separated using physical means

Which observation indicates that a chemical reaction has taken place?

• A substance becomes warmer

• A material changes from a solid to a liquid

• Bubbles form when a liquid is heated

• A new chemical substance is formed

Tags

NGSS.MS-PS1-2

How many atoms of carbon are included in one formula unit of the compound Na₂C₂O₄

• 2

• 4

• 6

• 8

Tags

NGSS.MS-PS1-1

Which of the following is an example of a compund?

• Copper

• Iron

• Carbon

• Water

Tags

NGSS.MS-PS1-1

Lighting a match and baking a cake are two actions that involve chemical changes. Why are these actions considered chemical changes?

• They change the state of matter

• They create new substances

• They change volume

• They create energy

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5