Respuesta :
Answer:
The molality of this solution is 0.368 molal
Explanation:
Step 1: Data given
Mass of CaCl2 = 10.2 grams
Molar mass of CaCl2 = 110.98 g/mol
Mass of water = 250 grams = 0.250 kg
Step 2: Calculate the number of moles CaCl2
Moles CaCl2 = mass CaCl2 / molar mass CaCl2
Moles CaCl2 = 10.2 grams / 110.98 g/mol
Moles CaCl2 = 0.0919 moles
Step 3: Calculate the molality of the solution
Molality solution = moles CaCl2 / mass water
Molality solution = 0.0919 moles / 0.250 kg
Molality solution = 0.368 mol / kg = 0.368 molal
The molality of this solution is 0.368 molal
Answer:
0.367 m
Explanation:
We have to start with the molality equation:
[tex]m=\frac{mol~of~solute}{Kg~of~solvent}[/tex]
If we want to calculate the molality we need the moles of the solute and the Kg of the solvent. In this case the solute is [tex]CaCl_2[/tex] and the solvent is [tex]H_2O[/tex].
Lets start with the the moles of solute. For this calculation we need the molar mass of [tex]CaCl_2[/tex] ([tex]111~g~CaCl_2[/tex]) and the mass, so:
[tex]10.2~g~CaCl_2\frac{1~mol~CaCl_2}{111~g~CaCl_2}[/tex]
[tex]0.0918~mol~CaCl_2[/tex]
Now, we can calculate the Kg of solvent, if we do the conversion from grams to Kg:
[tex]250~g~CaCl_2\frac{1~Kg}{1000~g}[/tex]
[tex]0.25~Kg[/tex]
With these values we can calculate the "molality":
[tex]m=\frac{0.0918~mol~CaCl_2}{0.25~Kg}[/tex]
[tex]m=0.3672[/tex]
I hope it helps!
