In: Chemistry
given an aqueous solution of ammonium nitrate with a molal concentration of 2.480 m. what are the mole fractions of ammonium nitrate and water?
molality = weight of substance*1000/gram molar mass * weight of solvent in gm
assume weight of solvent(H2O) = 1000gm
2.480 = weight of substance*1000/80*1000
weight of substance = 2.480*80 = 198.4gm
no of moles of NH4NO3 n1 = 198.4/80 = 2.48 moles
no of moles of water n2 = 1000/18 = 55.5 moles
mole fraction of NH4NO3 X1 = n1/n1+n2
= 2.48/2.48+55.5
= 2.48/57.98
= 0.0427
mole fraction of H2O X2 = n2/n1+n2
= 55.5/2.48+55.5
= 55.5/57.98
= 0.957