7.PS1.2 Elemental and Compound

Select all of the options that are compounds.

• Neon (Ne)

• Ozone (O_3)

• Water (H_2O)

• Nitrogen (N_2)

• Ammonia (NH_3)

Answer explanation

The compounds in the options are Ozone (O_3) and Water (H_2O), as they are made up of multiple elements bonded together.

Tags

NGSS.MS-PS1-1

The diagram shows different structures. Each structure represents a molecule of a substance.

• Table categorizing structures as elemental molecules

• Table categorizing structures as compound molecules

• Table categorizing structures as both elemental and compound molecules

• Table categorizing structures as neither elemental nor compound molecules

Answer explanation

The correct choice is to categorize structures as both elemental and compound molecules because the diagram shows different structures representing molecules of substances that can be either elemental or compound.

Tags

NGSS.MS-PS1-1

Which chemical formula represents a diatomic molecule?

• CO_2

• 2C

• O_2

• 2CO_3

Answer explanation

The correct choice is O_2 because diatomic molecules consist of two atoms of the same element bonded together. In this case, O_2 represents oxygen molecules bonded together.

The diagram models atoms in a material.

• The material contains only elemental molecules.

• The material contains two kinds of compound molecules and one elemental molecule.

• The material contains two kinds of elemental molecules and one compound molecule.

• The material contains only compound molecules.

Answer explanation

The material contains two kinds of elemental molecules and one compound molecule, as shown in the diagram.

Tags

NGSS.MS-PS1-1

Which two molecules are classified as compound molecules?

• ammonia

• hydrogen

• nitrogen

• ozone

• water

Answer explanation

The two molecules classified as compound molecules are ammonia and water.

Tags

NGSS.MS-PS1-1

Neon (chemical formula: Ne), a noble gas, is contained in a glass tube under pressure. Neon lights work by passing electric current through the pressurized gas, which causes the gas to glow. A student claims that the neon gas cannot act like a molecule since the atoms are not bonded together. Is the student’s claim correct or incorrect, and why?

• The student is correct because conducting electricity is not a molecular behavior.

• The student is correct because noble gases cannot exhibit molecular behaviors unless they bond to other elements.

• The student is incorrect because noble gases can exhibit molecular behaviors if they are diatomic molecules.

• The student is incorrect because conducting electricity is evidence of molecular behavior.

Answer explanation

The student is correct because noble gases cannot exhibit molecular behaviors unless they bond to other elements.

Which description correctly classifies the major and minor gases in the atmosphere?

• The major gases are diatomic molecules, and the minor gases are molecular compounds.

• The major gases are molecular compounds, and the minor gases are diatomic molecules.

• All of the gases are diatomic molecules.

• All of the gases are molecular compounds.

Answer explanation

The major gases are diatomic molecules, and the minor gases are molecular compounds.

Which model *only* shows elemental molecules?

• A

• B

• C

• D

Answer explanation

Model A only shows elemental molecules, as indicated in the question. Therefore, the correct choice is A.

Tags

NGSS.MS-PS1-1

Answer explanation

The correct statement is that CO2 is a compound molecule, and N2 is an elemental molecule.

Tags

NGSS.MS-PS1-1

Nitrogen naturally exists as a diatomic molecule. Which chemical formula represents a nitrogen molecule?

• N

• Nn

• 2N

Answer explanation

Nitrogen naturally exists as a diatomic molecule, so the correct chemical formula representing a nitrogen molecule is N2.

Tags

NGSS.MS-PS1-1