Part A. On a day with a temperature of 15°C and a pressure of 790.0 torr , how many grams of peroxyacyl nitrates are found in the air above Los Angeles (1500. km3) if the concentration is 30.0mol of peroxyacetyl nitrate per 1 billion moles of air (30 ppb)? The molar mass of the major peroxyacyl nitrate, peroxyacetyl nitrate, is 118.03 g / mol.
Express your answer to three significant figures and include the appropriate units.
Peroxyacyl nitrates (PANs) are secondary pollutants in photochemical smog. Free radical reactions catalyzed by ultraviolet light from the sun oxidize unburned hydrocarbons to aldehydes, ketones, and dicarbonyl compounds, whose secondary reactions create peroxyacyl radicals, which combine with nitrogen dioxide to form peroxyacyl nitrates. These dissociate only slowly into radicals and NO2, which means that they can carry nitrates to sites other than their place or origin to regions in the troposphere where ozone can be produced more readily. Peroxyacyl nitrates are both toxic and irritating and even dissolve more readily in water than ozone. Even a few parts per billion can cause eye irritation and higher concentrations can cause extreme damage to vegetation.
One of the highest concentrations of peroxyacyl nitrates has been found in the Los Angeles (LA) basin at 30.0 mol of peroxyacetyl nitrate per 1 billion moles of air (30 ppb), reaching its peak at mid-afternoon. Most of the pollution in the LA basin is created in an area of only 3000 km2 and the pollution depth below the inversion layer is normally about 500 m. This concentration was therefore found in 1500 km3 of air above Los Angeles.
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