Question

What is the mole fraction of `KI` in a solution made by dissolving 3.4 g of `KI` in 5.8 g of water?

Answer 1

`"Mole fraction"` `=` `"Moles of component"/"Moles of all species in solution"`

Explanation:

And thus, `"Mole fraction, KI"` `=` `"Moles of KI"/"Moles of KI + moles of water"`

`=((3.4*g)/(166.00*g*mol^-1))/((3.4*g)/(166.00*g*mol^-1)+(5.8*g)/(18.01*g*mol^-1))` `=` `0.060`

Note that the mole fraction of `"water"` here must be necessarily `1-0.060=0.94`. Why `"necessarily"`?

Note that `"mole fractions"`, as they are here, are dimensionless quantities.