Unit 4 Test Review

What explains the very high melting and boiling point of water

• Strong dipole-dipole bonds between water molecules
• Strong hydrogen bonds between water molecules
• Dispersion forces which are present in all molecules
• Asymmetrical shape of the polar bonds.

Hydrogen bonding occurs when hydrogen is bonded to N, O, or F.  Which of the following has hydrogen bonding?

• CBr₄
• NO₂
• H₂S
• NH₃

Which is the second strongest intermolecular force, after hydrogen bonding?

• dipole-dipole attraction
• London forces

All molecules have London forces between them, but dipole-dipole and hydrogen bonding are so much stronger that when they are present we can ignore London forces.  Which of these has ONLY London forces?

• I₂
• NH₃
• OCl₂
• SH₂

Which substance would have the weakest intermolecular forces of attraction?

• CH₄

• NaCl

• H₂O

• MgF₂

________________________ have the strongest intermolecular forces of attraction.

• Dipole- Dipole

• Dispersion

• Hydrogen Bonds

Intermolecular forces for: NH₃

• Dispersion Force

• Dipole dipole

• Hydrogen bonding

Which of the following has the lowest boiling point?

• CaCl₂
• PH₃
• Cl₂
• N₂

Many covalent substances are volatile liquids or gases at room temperature because

• the intermolecular forces of attraction holding the molecules together are weak.

• the covalent bonds within the molecules are easily broken.

• the electrostatic attraction between ions is a weak force that can be overcome easily.

• they consists of simple molecules that do not dissolve in water but dissolve in organic solvents.

The measure of the resistance to the flow of a liquid is called:

• vapor pressure.

• sublimation.

• viscosity.

• condensation.