When Gases Put On Airs

Ashes denote that fire was Respect the grayest pile For the departed creature s sake That hovered there awhile. 

Only the chemist can disclose Into what carbonates. 

I hemical reactions that involve gas-phase reactants, their prod- nets, or both are enormously pervasive, essential—and peculiar. Here we will catalog some proclivities of reactions involving the gas phase and illustrate them through examples that may seem surprisingly familiar. 

Most of the peculiarities of gas-phase reactions stem from the fact that gas-phase molecules are, on average, relatively far apart—relative, that is, to liquid- or solid-phase collections of molecules. They also fly 

The term radical may be familiar to watchers of the evening news. Political radicals may cause riots with their overreactions, and chemical radicals cause riots in the body overabundances of radical species have been blamed for aging processes and cancer. Previously we discussed how atoms like to collect or shed electrons until they have nice filled shells. Now we can point out that these nice filled shells almost always end up with an even number of electrons. Atoms, and molecules as it turns out, like to have an even number of electrons because electrons come in pairs. Like shoes in a shoe box, they fit together as a pair, one beside the other. When something occurs to cause an unpaired electron, a radical, that species tends to be very reactive it is looking for another electron. Free radicals in the gas phase increase the number of successful encounters significantly. 

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When a gas is put in contact with a solvent, some of the gas molecules will dissolve in the liquid. This process is usually exothermic, so the solubility of gases in water usually decreases with increasing temperature (Figure 9.10). When water is heated in a beaker, bubbles of air form on the side of the glass before the water boils. As the temperature rises, the dissolved air molecules begin to boil out of the solution long before the water itself boils. 

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