Unit 4 Part 2 Practice Test

Which of the following statements is true about O₂?

• The two atoms share 4 electrons.

• It has a double bond.

• Its electronegativity difference is 0.

• All of the above are true.

Answer explanation

All statements about O₂ are true: it shares 4 electrons (2 pairs), has a double bond, and the electronegativity difference between the two oxygen atoms is 0, confirming that they are identical.

Which of the following bonds would NOT be considered a type of intramolecular bond?

• hydrogen bond

• covalent bond

• metallic bond

• ionic bond

Answer explanation

A hydrogen bond is an intermolecular force, not an intramolecular bond. Intra means within a molecule, while hydrogen bonds occur between molecules. Covalent, metallic, and ionic bonds are all types of intramolecular bonds.

Which intermolecular force is responsible for the high surface tension of water?

• London dispersion forces

• Hydrogen bonds

• Covalent bonds

• Dipole-dipole forces

Answer explanation

The high surface tension of water is primarily due to hydrogen bonds, which are strong intermolecular forces that create a cohesive effect among water molecules, leading to a higher surface tension compared to other liquids.

Which intermolecular force is the weakest?

• London dispersion forces

• Hydrogen bonds

• Covalent bonds

• Dipole-dipole forces

Answer explanation

London dispersion forces are the weakest intermolecular forces, arising from temporary dipoles in molecules. In contrast, hydrogen bonds, covalent bonds, and dipole-dipole forces are stronger due to more significant interactions.

What is the only type of intermolecular force that could have an impact on a noble gas?

• London dispersion forces

• Hydrogen bonds

• Covalent bonds

• Dipole-dipole forces

Answer explanation

Noble gases are nonpolar and do not have permanent dipoles. The only intermolecular force that can affect them is London dispersion forces, which arise from temporary fluctuations in electron density.

Which statement about the molecule is NOT true?

• Electrons are equally shared.

• It contains a single bond.

• It is polar.

• Its electronegativity difference is 0.

Answer explanation

The statement 'It is polar' is NOT true because if electrons are equally shared and the electronegativity difference is 0, the molecule is nonpolar. Polar molecules have an unequal sharing of electrons.

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Which of the following statements is true about VSEPR theory?

• It is the tendency for electron pairs to want to be as far apart as possible because valence electrons are repulsed by each other.

• It is the tendency for electron pairs to want to be as far apart as possible because valence electrons are attracted to each other.

• It is the tendency for electron pairs to want to be as close together as possible because valence electrons are repulsed by each other.

• It is the tendency for electron pairs to want to be as close together as possible because valence electrons are attracted to each other.

Answer explanation

The correct statement reflects VSEPR theory, which states that electron pairs repel each other and thus arrange themselves to be as far apart as possible, minimizing repulsion among valence electrons.

Predict which substance has the weakest intermolecular forces at work.

• Substance #1

• Substance #2

• Substance #3

• Substance #4

Answer explanation

Substance #4 has the weakest intermolecular forces, likely due to its molecular structure or lower molecular weight, resulting in less attraction between molecules compared to the other substances.

Predict which substance is most likely to be an ionic compound.

• Substance #1

• Substance #2

• Substance #3

• Substance #4

Answer explanation

Substance #3 is most likely an ionic compound because it consists of a metal and a non-metal, which typically form ionic bonds due to the transfer of electrons, unlike the other substances that may be covalent.

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Which intermolecular force is the strongest?

• London dispersion forces

• Hydrogen bonds

• Covalent bonds

• Dipole-dipole forces

Answer explanation

Hydrogen bonds are the strongest intermolecular forces among the options listed. They occur between molecules with highly electronegative atoms like oxygen or nitrogen, leading to significant attraction compared to other forces.