Taking into account the definition of molality, the correct answer is the third option: the molality of the solution is 0.2 [tex]\frac{moles}{kg}[/tex].
Definition of molality
Molality is a measure of concentration that indicates the number of moles of solute that are dissolved in 1 kilogram of solvent.
This is, molality is the ratio of the number of moles of any dissolved solute to kilograms of solvent.
The Molality of a solution is determined by the expression:
[tex]molality=\frac{number of moles of solute}{kilograms of solvent}[/tex]
Molality in this case
In this case, you know:
- number of moles of solute: 8 grams×[tex]\frac{1 mole}{60 grams}[/tex]= 0.133 moles, being 60 [tex]\frac{grams}{mole}[/tex]the molar mass of acetic acid, that is, the amount of mass that a substance contains in one mole.
- kilograms of solvent: 725 grams= 0.725 kg (being 1000 grams= 1 kg)
Replacing in the definition of molality:
[tex]molality=\frac{0.133 moles}{0.725 kg}[/tex]
Solving:
molality= 0.18 [tex]\frac{moles}{kg}[/tex]≅ 0.2 [tex]\frac{moles}{kg}[/tex]
Finally, the correct answer is the third option: the molality of the solution is 0.2 [tex]\frac{moles}{kg}[/tex].
Learn more about molality:
brainly.com/question/20366625?referrer=searchResults
brainly.com/question/4580605?referrer=searchResults
