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Answers
Question:-6.055×10^-2kg of washing soda(Na2CO3.10H2O) is dissolved in water to obtain 1L of a solution of density 1077.2kg/m^3.Calculate the molarity,molality,and mole fraction of Na2CO3 in the solution......
Solution:-
In the beginning most students have confusion in molarity and molality....
let first understand this
Molarity=moles of solute/volume of solution
Molality=mass of solute/mass of solvent
Molefracion=mole of one solute/total moles of all solute present in solution
=>moles of solute=(6.055×10^-2×10^3)/(gram molecular mass
gram molecular mass=23g
moles of solute=60.55/23)=2.6moles
volume of solution=1L
molarity=moles of solute/volume of solution=2.6mol/litre
mass of solute=6.055×10^-2kg
mass of solution=volume×density=
density=1077.2kg/m^3=(1077.2/1000)kg/l=1.07kg/l
mass of solution=(1.07×1)kg
mass of solvent=mass of solution-mass of solute=1.07-.06=1.01kg
molality=mass of solute/mass of solvent=(6.05×10^-2)/1.01=6×10^-2
mole fraction of solute=moles of solute/total mole of solution
moles of solute=2.6
moles of water=mass of water/18=1×1000/18=55.6moles
mole fraction of solute=2.6/(55.6+2.6)
=2.6/58.2=.044
{hope it helps}
Answer:
In the beginning most students have confusion in molarity and molality....
let first understand this
Molarity=moles of solute/volume of solution
Molality=mass of solute/mass of solvent
Mole fracion=mole of one solute/total moles of all solute present in solution
=>moles of solute=(6.055×10^-2×10^3)/(gram molecular mass
gram molecular mass=23g
moles of solute=60.55/23)=2.6moles
volume of solution=1L
molarity=moles of solute/volume of solution=2.6mol/litre
mass of solute=6.055×10^-2kg
mass of solution=volume×density=
density=1077.2kg/m^3=(1077.2/1000)kg/l=1.07kg/l
mass of solution=(1.07×1)kg
mass of solvent=mass of solution-mass of solute=1.07-.06=1.01kg
molality=mass of solute/mass of solvent=(6.05×10^-2)/1.01=6×10^-2
mole fraction of solute=moles of solute/total mole of solution
moles of solute=2.6
moles of water=mass of water/18=1×1000/18=55.6moles
mole fraction of solute=2.6/(55.6+2.6)
=2.6/58.2=.044