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Ch.13 - Solutions
Chapter 13, Problem 49

Calculate the mass of nitrogen dissolved at room temperature in an 80.0-L home aquarium, assuming a total pressure of 1.0 atm and a mole fraction for nitrogen of 0.78.

Verified step by step guidance
1
Identify the relevant law: Use Henry's Law, which states that the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas above the liquid.
Calculate the partial pressure of nitrogen: Multiply the total pressure by the mole fraction of nitrogen, i.e., PN2=1.0 atm×0.78.
Use Henry's Law to find the concentration of nitrogen: C=kH×PN2, where kH is the Henry's Law constant for nitrogen at room temperature.
Determine the volume of water in the aquarium: Since the aquarium is 80.0 L, assume this is the volume of water available for dissolving nitrogen.
Calculate the mass of nitrogen: Use the concentration from Henry's Law and the volume of water to find the moles of nitrogen, then convert moles to mass using the molar mass of nitrogen (28.02 g/mol).