Question

What is the mole fraction of sulfuric acid in a solution made by adding 34 g of sulfuric acid (H2SO4 = 98 g/mol) to 100 g of water (H2O = 18 g/mol)?

Answer 1

Answer:

Mole Fraction  =  0.059

Explanation:

To find the mole fraction, you need to (1) convert grams H₂SO₄ and H₂O to moles (via molar mass) and then (2) calculate the mole fraction.

(Step 1)

Molar Mass (H₂SO₄): 98 g/mol

34 grams H₂SO₄            1 mole
--------------------------  x  -------------------  =  0.347 moles H₂SO₄
                                      98 grams

Molar Mass (H₂O): 18 g/mol

100 grams H₂O              1 mole
-------------------------  x  --------------------  =  5.56 moles H₂O
                                      18 grams

(Step 2)

                                             moles solute
Mole Fraction  =  -------------------------------------------------
                               moles solute + moles solvent

                                              0.347 moles H₂SO₄
Mole Fraction  =  -----------------------------------------------------------
                               0.347 moles H₂SO₄ + 5.56 moles H₂O

Mole Fraction  =  0.059