Question

Calcule la molalidad de una 20g Ca Cl₂ en 250g de que contiene solucion H₂O.

Answer 1

Answer:

The solution is 0, 90 molal. See the explanation below, please

Explanation:

Molality is defined as moles of solute in 1 kg of solvent (1000 grams). The following three simple rule must be performed:

We calculate the weight of 1 mol of CaCl2

Weight Ca =40, 078 g

Weight Cl= 35, 453 g

Weight of 1 mol of CaCl2=40, 078g + 2x (35, 453g )= 110, 98g

110, 98 g ---1 mol

25 g---X= (25g x1 mol)/110, 98g= 0,23mol

250g solvent -----0,23 mol CaCl2 (the solute)

1000g solvent ----X = (1000g x0,23mol)/250g =0,90 mol solute

The solution is 0,90 molal