Question

Se disuelven 30,0 g de Cloruro de Sodio en 90,0 g de agua a 25oC. Calcular la fracción molar de NaCl en la solución.

Answer 1

Mm NaCl = 58.45 g/mol
        H2O  = 18 g/mol

n = mol/Mm

nsto = 30 g / 58.45 g/mol = 0.513 mol de sal

nsolvente = 90 g/ 18 g/mol = 5 mol

ntotal = sto + n svte

n total = (0.513 mol + 5 mol ) = 5.513 mol

Xsto =        n sto
           ````````````````````
                   n total

Xsto =    0.513 mol
             ````````````````
               5.513 mol

Xsto = 0.09 (sal)
                

Xsvte =        n svte
           ````````````````````
                   n total

Xsvte =      5 mol
             ````````````````
               5.513 mol

Xsvte = 0.90 (agua)