Question

¿Cuál es la molalidad de una solución que contiene 128 g de metanol CH3OH en 108 g de agua?

Answer 1

Mm CH3OH = 32 g/mol

1. calcular moles de soluto

n = 128 g CH3OH  x  1mol CH3OH
                                   ``````````````````
                                   32 g CH3OH

n = 4 moles

2. convertir g a Kg

Kg = 108 / 1000 = 0.108 Kg de agua

3. calcular molalidad

m = mol soluto
       ``````````````
         Kg svte

m = 4 moles
      ``````````````
       0.108 Kg

m = 37.03 molal