Problem 14
Assuming that the octet rule applies, draw the Lewis structure for each of these molecules. a. \(\mathrm{CCl}_{4}\) (carbon tetrachloride, a substance formerly used as a cleaning agent) b. \(\mathrm{H}_{2} \mathrm{O}_{2}\) (hydrogen peroxide, a mild disinfectant; the atoms are bonded in this order: \(\mathrm{H}-\mathrm{O}-\mathrm{O}-\mathrm{H})\) c. \(\mathrm{H}_{2} \mathrm{~S}\) (hydrogen sulfide, a gas with the unpleasant odor of rotten eggs) d. \(\mathrm{N}_{2}\) (nitrogen gas, the major component of the atmosphere) e. HCN (hydrogen cyanide, a molecule found in space and a poisonous gas) f. \(\mathrm{N}_{2} \mathrm{O}\) (nitrous oxide, "laughing gas"; the atoms are bonded \(\mathrm{N}-\mathrm{N}-\mathrm{O}\) ) g. \(\mathrm{CS}_{2}\) (carbon disulfide, used to kill rodents; the atoms are bonded \(S-C-S\) )
Problem 15
Several oxygen species play important chemical roles in the stratosphere, including oxygen atoms, oxygen molecules, ozone molecules, and hydroxyl radicals. Draw Lewis structures for each.
Problem 19
Arrange these types of radiation in order of increasing energy per photon: gamma rays, infrared radiation, radio waves, visible light.
Problem 20
The microwaves in home microwave ovens have a frequency of \(2.45 \times 10^{9} \mathrm{~s}^{-1}\). Is this radiation more or less energetic than radio waves? Than X-rays?
Problem 21
Ultraviolet radiation is categorized as UV-A, UV-B, or UV-C. Arrange these types in order of increasing: a. wavelength b. energy c. potential for biological damage
Problem 22
Draw Lewis structures for any three different CFCs.
Problem 23
CFCs were used in hair sprays, refrigerators, air conditioners, and plastic foams. Which properties of CFCs made them desirable for these uses?
Problem 24
a. Can a molecule that contains hydrogen be classified as a CFC? b. What is the difference between an HCFC and an HFC?
Problem 26
These free radicals all play a role in catalyzing ozone depletion reactions: \(\mathrm{Cl} \cdot, \cdot \mathrm{NO}_{2}, \mathrm{ClO} \cdot\), and \(\cdot \mathrm{OH}\). a. Count the number of outer electrons available and then draw a Lewis structure for each free radical. b. What characteristic is shared by these species that makes them so reactive?
Problem 29
The EPA has used the slogan "Ozone: Good Up High, Bad Nearby" in some of its publications for the general public. Explain the message.
