Unit 3: Intermolecular Forces (IMFs)

Which statement best defines intermolecular forces (IMFs)?

• Attractions between molecules due to electrostatic effects

• Attractions between ions forming ionic bonds

• Attractions causing nuclei to fuse into larger atoms

• Attractions between atoms within one molecule

Compared to chemical bonds, IMFs are generally

• stronger and more permanent interactions

• weaker and involve no true bonding

• unrelated to molecular properties

• equal in strength and permanence

Which physical property typically increases as IMFs become stronger?

• Boiling point of a pure substance

• Volatility of a nonpolar gas

• Ease of evaporation at room temperature

• Vapor pressure of a liquid sample

Which set correctly pairs high IMFs with the property trend?

• Higher value

• Viscosity

• Lower value

• Boiling point

• Higher value

• Surface tension

• Higher value

• Vapor pressure

Hydrogen bonding doesn't occur when H is bonded to which of these atoms in a molecule?

• Chlorine atoms in a molecule

• Nitrogen atoms in a molecule

• Oxygen atoms in a molecule

• Fluorine atoms in a molecule

Why are hydrogen bonds significant in biology?

• They create metallic bonding in cells

• They ionize all amino acids fully

• They prevent diffusion across membranes

• They hold DNA bases together in pairs

Water has a high specific heat primarily because

• its electrons are fully delocalized

• its low mass increases heat capacity

• its ionic bonds absorb heat strongly

• its hydrogen bonds require energy to disrupt

Which statement about hydrogen bonds is accurate?

• They are chemical bonds forming new compounds

• They are relatively weak but crucial for life

• They occur only in gaseous hydrogen

• They are strongest at very high temperatures

Dipole-dipole forces arise between

• opposite partial charges of polar molecules

• two nonpolar molecules without charges

• ionic crystals with full charges

• atoms in a metallic lattice

Which example illustrates an induced dipole moment?

• O2 becoming temporarily attracted to water

• NaCl dissolving into separate ions

• N2 permanently gaining ionic charge

• H2O forming covalent bonds with O2