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General Chemistry Donald McQuarrie Peter A. Rock • Ethan Gallogly, University Sc

ID: 990001 • Letter: G

Question

General Chemistry Donald McQuarrie Peter A. Rock • Ethan Gallogly, University Science Books presented by Sapling Learning The quantity of atmospheric SO2(9) can be determined by reaction with H202(aq, according to the balanced chemical equation shown below. H,0,(aq + SO. ) > H,Sofaaa) The amount of sulfuric acid produced can be determined by titration with sodium hydroxide of known concentration. An 687.0 gram sample of an air that is known to contain sulfur dioxide was reacted with excess hydrogen peroxide. Given that 1850 mL of a 0.00250 M NaOH(aq) were required to neutralize the H2SO4(aq) produced, calculate the mass percentage of SO29in the air sample. Number % so , (3)

Explanation / Answer


H2O2 + SO2 -----> H2SO4
1 mole of SO2 produces 1 mole of H2SO4
H2SO4 + 2 NaOH -----> Na2SO4 + 2 H2O
1 moles of H2SO4 require 2 moles of NaOH
number of moles of NaOH = 0.0025 *18.50/1000 = 4.625 * 10^-5
number of moles of H2SO4 = 4.625*10^-5/2 = 2.3125 * 10^-5
number of moles of SO2 = 2.3125 * 10^-5
mass of SO2 = 2.3125 * 10^-5 * 64 = 0.00148 g
Percentage of SO2 = 0.00148/687 * 100 = (2.1543 * 10^-4)%