Question

A mixture contains 21.7 g NaCl 3.74 g KCI and 9.76 g LiCl. How many moles of NaCl are in the mixture?

Answer 1

Well, what is the formula mass of sodium chloride?

Explanation:

I make it `58.44*g*mol^-1`...and so divide the mass of salt by its formula mass...

`n_"NaCl"=(21.7*g)/(58.44*g*mol^-1)=??*mol`

I suspect that this question originally asked for the mole fraction of sodium chloride in the mixture...

`chi_"NaCl"="moles of sodium chloride"/"total moles in the mixture"`

`chi_"NaCl"=((21.7*g)/(58.44*g*mol^-1))/((21.7*g)/(58.44*g*mol^-1)+(3.74*g)/(74.55*g*mol^-1)+(9.76*g)/(42.39*g*mol^-1))`

Will `chi_"NaCl"+chi_"KCl"+chi_"LiCl"=1`....Why?