Chapter 12

Explain condensation and dynamic equilibrium.

What is the vapor pressure of a substance? How does it depend on the temperature and strength of intermolecular forces?

Explain how sweat cools the body.

Explain why a steam burn from gaseous water at \(100{ }^{\circ} \mathrm{C}\) is worse than a water burn involving the same amount of liquid water at \(100{ }^{\circ} \mathrm{C}\).

Explain what happens when a liquid boils.

Explain how ice cubes cool down beverages.

Is the melting of ice endothermic or exothermic? What is the sign of \(\Delta H\) for the melting of ice? For the freezing of water?

Is the boiling of water endothermic or exothermic? What is the sign of \(\Delta H\) for the boiling of water? For the condensation of steam?

What are dispersion forces? How does the strength of dispersion forces relate to molar mass?

What are dipole-dipole forces? How can you tell whether a compound has dipole- dipole forces?