Question

la densidad de una disolucion que contiene 50g de talueno (C₆H₈) y 225g de benceno (C₆H₆) es de o,876 g/ml. la molaridad (M) de la disolucion es:

a)2,1 M
b)0,02 M
c)1,2 M
d)0,21 M

Answer 1

masa = 50 g    

Mm C7H8 = 92 g/mol

1. calcula volumen aplicando la fórmula de densidad

d = m/v

v = 225 g / 0.876 g/mL

V = 256 mL

2. calcular moles de soluto

n = m/Mm

n = 50 g / 92 g/mol

n = 0.543 moles

3. calcular la molaridad

M = n / v(L)

M = 0.543 mol / 0.256 L

M = 2.12 molar ( respuesta a)

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nota: revisar fórmula del Tolueno: C7H8 / C6H5CH3