Pre-AP CHEM Unit 6 Day 5 Review

The molecule AX₃ is polar and obeys the octet rule; therefore, the central atom A

• has no lone pairs of electrons
• has one lone pair of electrons
• has two lone pairs of electrons
• has three lone pairs of electrons

Which of the following statements about polarity is false?

• Linear molecules can be polar.
• CCl₄ is a polar molecule.
• Dipole moments can “cancel”, giving a net non-polar molecule.
• Lone (unshared) pairs of electrons on the central atom play an important role in influencing polarity.

Which is the most polar molecule?

• CH₄
• CF₄
• H₂O
• CO₂

CHF₃ is ________ polar than CHBr₃ because

• more; the C-F bonds are more polar than the C-Br bonds.
• less; the C-F bonds are less polar than the C-Br bonds.
• more; the C-H bond in CHF₃ is a non-polar bond.
• less; the C-H bond in CHF₃ is a non-polar bond.

What is the Lewis structure of water with the correct partial charges and non-bonding electrons?

• A
• B
• C
• D

Which of the molecules contains polar covalent bonds but is NOT itself a polar molecule?

• I
• II
• III
• ¯\_(ツ)_/¯

Consider the two water molecules pictured.  Which statement is correct?

• The covalent bond A is stronger than the hydrogen bond B.
• The covalent bond B is stronger than the hydrogen bond A.
• The hydrogen bond B is stronger than the covalent bond A.
• The hydrogen bond A is stronger than the covalent bond B.

What types of intermolecular interactions does chloroform (CH₃Cl) exhibit?
I) London dispersion
II) dipole-dipole
III) hydrogen bonding
IV) covalent bonding

• I only
• I and II only
• I and III only
• I, II, and III only

In which of these compounds would you find ONLY dispersion forces existing between the molecules?
I. NH₃
II. CCl₄
III. CH₂Cl₂
IV. HBr

• I, III, and IV only
• I and IV only
• III only
• II only

Considerthe following 4 forces or interactions:
covalent bonding; 
dispersion forces; 
hydrogen bonding; 
dipole-dipole interactions
Which of the following correctly lists these four types of interactions/forces according to increasing strength (weakest to strongest)?

• covalent; hydrogen; dipole; dispersion
• dispersion; hydrogen; dipole; covalent
• covalent; dipole; hydrogen; dispersion
• dispersion; dipole; hydrogen; covalent