Chapter 12
2) Automotive organic emissions contain more alkenes and aromatics and less of the less reactive alkanes
5) Alkenes can react by addition to the double bond, which alkanes, having no double bonds, cannot.
6) An aromatic ring has a low H/C ratio, and is very stable because of resonance in the ring. Other compounds with low H/C ratios have many double and triple bonds which provide active reaction sites.
Chapter 13
3) A reducing smog will not have high levels of oxidants such as ozone, atomic oxygen, PAN or PBN. However, SO2 is rapidly oxidized to SO3 in an oxidizing atmosphere. Therefore, SO2 will only exist at high levels in a sulfurous or reducing smog.
5) PAN is produced after NO and atomic oxygen are formed, react with hydrocarbons to form free radicals and these free radicals react with NO2 forming PAN and other nasty compounds. It therefore occurs late in the smog-forming process.
7) Oxidants peak last in the daily smog production. Earlier in the day, oxidants are used up as they are formed by reaction with the hydrocarbons.
8) The alkylperoxyl radicals, ROO· rapidly oxidize NO to NO3.
13) CO is an indicator of automotive traffic so might be used as a standard. However, CO can be formed from the photolysis of formic acid (see eqn 13.5.35) and can also be oxidized by any of the oxidants in smog, for example: CO + HO. + O2 -> CO2 + HOO.
18) Rubber is is an unsaturated polymer, the unsaturated double bonds making kinks in the polymer chain, which is what lets it stretch and rebound. Since it is unsaturated, ozone can readily attack and break the chains at the reactive double bonds.