Question 1

Which of the following statements best explains why water (H$$_2O) $$has a higher boiling point than methane (CH$$_4$$)?

Accepted Answer

Water molecules experience hydrogen bonding, which is a stronger intermolecular force than the dispersion forces present in methane.

Question 2

How many valence electrons are present in a molecule of SF$$_6$$?

Accepted Answer

$$48$$

Question 3

Which of the following molecules would be expected to experience hydrogen bonding?

Accepted Answer

NH$$_3$$

Question 4

What is the molecular shape of CO$$_2$$ according to VSEPR theory?

Accepted Answer

Linear

Question 5

Which of the following best describes the bond in HCl?

Accepted Answer

Polar covalent bond

Question 6

A molecule of CCl$$_4 is $$nonpolar even though it contains polar bonds. Why?

Accepted Answer

The four C–Cl dipoles cancel out due to the tetrahedral symmetry of the molecule.

Question 7

Which of the following molecules would dissolve best in cyclohexane (a nonpolar solvent)?

Accepted Answer

Octane (C$$_8H$_{18})$$

Question 8

What is the total number of valence electrons in a molecule of BF$$_3$$?

Accepted Answer

$$24$$

Question 9

Which of the following intermolecular forces is the strongest?

Accepted Answer

Hydrogen bonding

Question 10

Which of the following molecules is expected to have a bent molecular shape?

Accepted Answer

H$$_2O$$

Question 11

What is the difference in electronegativity between oxygen and hydrogen, and what type of bond does this produce in H$$_2O$$?

Accepted Answer

Oxygen: $$3.5$$, Hydrogen: $$2.1$$, Difference: $$1.4$$, polar covalent bond

Question 12

Which of the following best describes the electron group geometry and molecular shape of NH$$_3$$?

Accepted Answer

Electron group geometry: tetrahedral; molecular shape: trigonal pyramidal

Question 13

Which of the following molecules would experience only dispersion forces?

Accepted Answer

CH$$_4$$

Question 14

A molecule has a central atom with three groups attached and no lone pairs. What is its molecular shape?

Accepted Answer

Trigonal planar

Question 15

Which of the following is a requirement for a molecule to experience hydrogen bonding?

Accepted Answer

It must contain a very polar bond with H attached to N, O, or F, and another molecule with a lone pair of electrons.

Question 16

Which of the following best explains why ionic compounds generally have higher melting points than covalent compounds?

Accepted Answer

Ionic bonds are stronger than covalent bonds due to the electrostatic attraction between oppositely charged ions.

Question 17

Which of the following molecules is polar and has a trigonal pyramidal shape?

Accepted Answer

NH$$_3$$

Question 18

If a molecule has two bonding pairs and two lone pairs on the central atom, what is its molecular shape?

Accepted Answer

Bent

Question 19

Which of the following best describes the intermolecular forces present in SO$$_2$$?

Accepted Answer

Dispersion forces and dipole-dipole interactions

Question 20

Which of the following molecules would have the highest boiling point due to hydrogen bonding?

Accepted Answer

H$$_2O$$

Molecular Shapes, Lewis Dot Structures, and Their Impact

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