Calculate the masses of oxygen and nitrogen that are dissolved in 6.0 L of aqueous solution in equilibrium…?

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I’m having a little trouble with this chem. question… I took the partial pressures, then used those to find the molarity using Henry’s law, then found the number of moles. then I used the molar mass to find the mass in mg… what would you do?Here is the entire question Calculate the masses of oxygen and nitrogen that are dissolved in 6.0 L of aqueous solution in equilibrium with air at 25 °C and 760 Torr. Assume that air is 21% oxygen and 78% nitrogen by volume.Gas constants are O2 7.9×10^2 bar/M N2 1.6x 10^3 bar/M

Mr. Toni Zulauf Sr. · Accepted Answer

Henry’s Law c = p/k, where p = partial pressure and k = Henry’s constant for the gas.. Partial pressure is proportional to volume fraction, 760 torr = 1 atm so p(O2) = 0.21 atm, p(N2) = 0.78 atm k for O2 = 769.2 L-atm/molk for N2 = 1639 L-atm/mol c(O2) = 0.21/769.2 = 2.73*10^-4 mol/Lc(N2) = 0.78/1639 = 4.76*10^-4 mol/LThere are 6.0 L of solution, so the no of moles isn(O2) = 6* 2.73*10^-4 = 1.64*10^-3 moln(N2) = 6*4.76*10^-4 = 2.86*10^-3 molThe molar mass of O2 = 32 so there are 32*1.64*10^-3 = 52 mg of O2 The molar mass of N2 = 28 so there are 28*2.86*10^-3 = 80 mg of N2

Mr. Toni Zulauf Sr. · Answer

you want to envision an ICE chart (I = initial, C = replace, E = equilibrium) for a weak acid. HB = cinnamic acid on the best of the chart, think about HB –> H+ + B- The initial quantity of HB is a million.6*10^-3 The replace for HB is -x, at the same time as the replace for H+ and B- is +x The equilibrium quantity for HB is a million.6*10^-3 – x The equilibrium quantity for H+ is x. Ka = [H+]^2/[HB] So Ka = x^2/(a million.6*10^-3 – x) because x is this style of small variety, it must be removed from the denominator with out causing a lot disturbance. so that you’re left with Ka = x^2/a million.6*10^-3 After plugging in Ka and fixing for x, you get: x = 2.40 3*10^-4 = [H+] -log ([H+]) = pH pH = 3.sixty one

Sigrid O'Kon

Calculate the masses of oxygen and nitrogen that are dissolved in 6.0 L of aqueous solution in equilibrium…?

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