In: Chemistry
A solution is 5.66 % by mass NH3 (MM 17.04 g/mol) in water (MM 18.02 g/mol). The density of the resulting solution is 0.974 g/mL. What is the mole fraction, molarity and molality of NH3 in the solution?
5.66% by mass NH3 5.66g of NH3 present in 100g of water
mass of slution = mass of solute + mass of solvent
= 5.66+100 = 105.66g
volume of solution = mass of solution * density of solution
= 105.66*0.974 = 102.91g
molality = W*1000/G.M.Wt* weight of solvent in g
= 5.66*1000/17.04*100 = 3.32m
molarity = W*1000/G.M.Wt* volume of solution in ml
= 5.66*1000/17.04*105.66 = 3.14M
no of moles of NH3 nNH3 = W/G.M.Wt = 5.66/17.04 = 0.332 moles
no of moles of H2O nH2O = W/G.M.Wt = 100/18.02 = 5.549 moles
mole fraction of NH3 XNH3 = nNH3/nNH3+ nH2O
= 0.332/0.332+5.549
= 0.332/5.881 = 0.0564