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The nitrogen content of organic compounds can be determined by the Dumas method. The compound in question is first reacted by passage over hot CuO(s):
The product gas is then passed through a concentrated solution of KOH to remove the CO2. After passage through the KOH solution, the gas contains N2 and is saturated with water vapor. In a given experiment a 0.253-g sample of a compound produced 31.8 mL N2 saturated with water vapor at 25°C and 726 torr. What is the mass percent of nitrogen in the compound? (The vapor pressure of water at 25°C is 23.8 torr.)
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