Química Ambiental e Reações

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18 Chemistry of the Environment Solutions to Exercises 18.72 (a) + + (b) 2CH₄(g) 2CO(g) + (c) vol CH₄ vol O₂ volume air = 0.20948) Equal volumes of gases at the same temperature and pressure contain equal numbers of moles (Avogadro's law). If 2 moles of O₂ are required for 1 mole of CH₄, 2.0 L of pure O₂ are needed to burn 1.0 L of vol O₂ = X = O₂ = 0.20948 2.0L = air 18.73 (a) According to Section 13.3, the solubility of gases in water decreases with increasing temperature. Thus, the solubility of CO₂(g) in the ocean would decrease if the temperature of the ocean increased. (b) If the solubility of in the ocean decreased because of global warming, more CO₂(g) would be released into the atmosphere, perpetuating a cycle of increasing temperature and concomitant release of from the ocean. 18.74 Most of the 390 watts/m² radiated from Earth's surface is in the infrared region of the spectrum. Tropospheric gases, particularly CH₄(g), and CO₂(g), absorb much of this radiation and prevent it from escaping into space (Figures 18.11 and 18.12). The energy absorbed by these so-called "greenhouse gases" warms the atmosphere close to Earth's surface and makes the planet livable. 18.75 Given 168 watts/m² at 10% efficiency, find the land area needed to produce 12,000 megawatts. 12,000 megawatts = 12,000 = 1.2 watts. 168 watts/m² (0.10) = 16.8 watts/m² solar energy possible with current technology. 1.2 10¹⁰ watts =7.143 = 7.1 10⁸ 16.8 watts The land area of New York City is 830 km², which is 830 X 10⁶ m². The area needed for solar energy harvesting to provide peak power would then be 7.143 10⁶ 10⁸ = 0.86 830 times the land area of New York City. 18.76 (a) NO(g) + hv N(g) + O(g) (b) NO(g) + hv (c) NO(g) + O₃(g) + (d) + 2HNO₃(aq) + NO(g) 18.77 (a) is a relatively strong Brønsted-Lowry base and produces OH- in aqueous solution according to the hydrolysis reaction: 1L (aq) + Kb = 1.8 10⁻⁴ If is sufficient for the reaction quotient, Q to exceed for Mg(OH)₂, the solid will precipitate. 566