Chapter 12

List these substances in order of decreasing boiling point: $$ \mathrm{CO}_{2}, \mathrm{Ne}, \mathrm{CH}_{3} \mathrm{OH}, \mathrm{KF} $$

Draw a Lewis structure for each molecule and determine its molecular geometry. What kind of intermolecular forces are present in each substance? (a) \(\mathrm{H}_{2} \mathrm{Se}\) (b) \(\mathrm{SO}_{2}\) (c) \(\mathrm{CHCl}_{3}\) (d) \(\mathrm{CO}_{2}\)

Draw a Lewis structure for each molecule and determine its molecular geometry. What kind of intermolecular forces are present in each substance? (a) \(\mathrm{BCl}_{3}\) (remember that \(\mathrm{B}\) is a frequent exception to the octet rule) (b) \(\mathrm{HCOH}\) (carbon is central; each \(\mathrm{H}\) and \(\mathrm{O}\) bonded directly to \(C\) ) (c) \(C S_{2}\) (d) \(\mathrm{NCl}_{3}\)

The melting point of ionic solids depends on the magnitude of the electrostatic attractions that hold the solid together. Draw ionic Lewis structures for \(\mathrm{NaF}\) and \(\mathrm{MgO}\). Which do you think has the higher melting point?

One prediction of global warming is the melting of global ice, which may result in coastal flooding. A criticism of this prediction is that the melting of icebergs does not increase ocean levels any more than the melting of ice in a glass of water increases the level of liquid in the glass. (a) Is this a valid criticism? Does the melting of an ice cube in a cup of water raise the level of the liquid in the cup? Why or why not? A response to this criticism is that scientists are not worried about rising ocean levels due to melting icebergs; rather, scientists are worried about rising ocean levels due to melting ice sheets that sit on the continent of Antarctica. (b) Would the melting of the ice sheets increase ocean levels? Why or why not?

Explain why rubbing alcohol feels cold when applied to the skin.