what is relation between molarity,molality,mass fraction,mole fraction?

Question

It is from the chapter solutions

Answer 1

Hello Nyra,

 

Molarity, molality, mass fraction, and mole fraction all tell you the relationship between the quantities of different substances in a mixture.  Each one has a different way of expressing the relationship because there are different ways to measure a quantity.  For instance, a given substance can have a mass, volume, and that mass can be converted to moles. 

 

Molarity is the relationship between a specific solute measured in moles and the solvent measured in liters (volume). Moles/L

 

Molality is pretty much the same except the solvent is measured in kg (mass). Moles/kg

 

Mole and mass fractions are ways of comparing multiple quantities of substances in a mixture but all measurements are measured in kg (mass fractions) or moles (mole fractions). Each substance gets its own mole or mass fraction, which is the moles or mass of that substance over the total moles or mass of everything.  This means that all the mole or mass fractions add up to 1.

moles/moles or kg/kg.

 

Hope this helps!

 

Jon

Answer 2

Hi Nyra!

Molarity, Molality, Mass Fraction and Mole Fraction are all measurements of concentration. 
Molarity = moles of solute/L of solution

Molality = moles of solute/kg of solution

Mass Fraction = Mass of one component / Mass all components

Mole Fraction = Moles of one component / total number of moles of all components