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Subject:
Chemistry [1]
Zinc metal reacts with excess hydrochloric acid to produce hydrogen gas according to the following equation: Zn(s) + 2HCl(aq) ZnCl2(aq) + H2(g) The product gas, H2, is collected over water at a temperature of 25 oC and a pressure of 754 mm Hg. If the wet H2 gas formed occupies a volume of 8.73 L, the number of grams of H2 formed is 0.691 g. The vapor pressure of water is 23.8 mm Hg at 25 oC. Feedback: The total pressure over the water in the collection vessel is equal to the sum of the partial pressure of H2 and the vapor pressure of water at 25.0. Therefore the partial pressure of H2 is calculated as PH2 = Ptotal - PH2O = 754 mm Hg - 23.8 mm Hg = 730 mm Hg