(a) Determine whether the reaction is first order or second order.
(b) What is the rate constant?
(c) What is the half-life?
Step 1 of 5) Sunlight penetrates well only 200 m into the water; the region between 200 m and 1000 m deep is the “twilight zone,” where visible light is faint. Below 1000 m, the ocean is pitch-black and cold, about 4 °C. The transport of heat, salt, and other chemicals throughout the ocean is influenced by these changes in the physical properties of seawater, and in turn the changes in the way heat and substances are transported affects ocean currents and the global climate. The sea is so vast that if the concentration of a substance in seawater is 1 part per billion (1 * 10-6 g>kg of water), there is 1 * 1012 kg of the substance in the world ocean. Nevertheless, because of high extracting costs, only three substances are obtained from seawater in commercially important amounts: sodium chloride, bromine (from bromide salts), and magnesium (from its salts).Absorption of CO2 by the ocean plays a large role in global climate. Because carbon dioxide and water form carbonic acid, the H2CO3 concentration in the ocean increases as the water absorbs atmospheric CO2. Most of the carbon in the ocean, however, is in the form of HCO3 - and CO3 2- ions, which form a buffer system that maintains the ocean’s pH between 8.0 and 8.3. The pH of the ocean is predicted to decrease as the concentration of CO2 in the atmosphere increases, as discussed in the “Chemistry and Life” box on ocean acidification on page 792.