How do you calculate mole fractions?

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Answer 1 · 2014-03-11T00:09:28

Mole fraction is a way to express the concentration of different components of a solution.

Let us consider you prepare a solution by dissolving n moles of salt in m moles of water.

Mole fraction of salt in solution = moles of salt / ( moles of salt + moles of water)

Mole fraction of salt = n / ( n + m)

Mole fraction of water = moles of water / ( moles of salt + moles of water)

Mole fraction of water = m / ( n + m)

Let us consider you prepare a solution by dissolving 3 moles of salt in 6 moles of water.

Mole fraction of salt in solution = moles of salt /( moles of salt + moles of water)

Mole fraction of salt = 3 / ( 3 + 6) = 3/9 = 0.33

Mole fraction of water = moles of water / ( moles of salt + moles of water)

Mole fraction of water = 6 / ( 3 + 6) = 6/9 = 0.66