Question

Calculate the mass of nitrogen dissolved at room temperature in 91.0 LL of the water contained within a home aquarium. Assume a total pressure of 1.0 bar, Henry's law constant for N2N2 of 6.1×10⁻⁴ mol L^-1 bar^-1and a mole fraction for nitrogen of 0.78.

Answer 1

Raoult's law: According to the Raoult's law in the mixture the partial pressure of a gas is equal to the product of its mole fraction and the total pressure of gases: Pa = XA Prontal by daltons law p=partial pressure of N2 Here; P., partial pressure of gas A, Praal vapor pressure of mixture and x, is the mole fraction of gas A. p=0.78*1 = 0.78 bar Henry's law: by henry's law p=Kh*C Kh(N2) = 6.1*10-4 mol L-1 bar-1 p= 0.78 bar According to Henry's law at any given temperature the solubility of gas is directly proportional to its partial pressure. COCP C = KP C =k* p Here; = 6.1x10-4 mol L-1 bar-1 *0.78 bar =4.758*10^-4 mole /L C = concentration of gas k = proportionality constant P=partial pressure Given that volume 91.0 L The solubility of gases is decrease with increasing temperature and increasing with increasing pressure. so for 91 L solution moles = molarity * volume =4.758*10^-4 mole /L *91 = 0.0433 moles Amount Of N2 number of moles * molar ass = 0.0433 * 28 =1.2123384 gm = 1.21 gm