Respuesta :
Answer: The molality of NaOH in the solution is 0.551 m
Explanation:
To calculate mass of a substance, we use the equation:
[tex]\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}[/tex]
Density of solution = 1.15 g/mL
Volume of solution = 1 L = 1000 mL (Conversion factor: 1 L = 1000 mL)
Putting values in above equation, we get:
[tex]1.15 g/mL=\frac{\text{Mass of solution}}{1000mL}\\\\\text{Mass of solution}=(1.15g/mL\times 1000mL)=1150g[/tex]
We are given:
Mass of solute (NaOH) = 24.8 grams
Mass of solution = 1150 grams
Mass of solvent = Mass of solution - mass of solute = [1150 - 24.8] g = 1125.2 g
To calculate the molality of solution, we use the equation:
[tex]Molality=\frac{m_{solute}\times 1000}{M_{solute}\times W_{solvent}\text{ (in grams)}}[/tex]
Where,
[tex]m_{solute}[/tex] = Given mass of solute (NaOH) = 24.8 g
[tex]M_{solute}[/tex] = Molar mass of solute (NaOH) = 40 g/mol
[tex]W_{solvent}[/tex] = Mass of solvent = 1125.2 g
Putting values in above equation, we get:
[tex]\text{Molality of }NaOH=\frac{24.8\times 1000}{40\times 1125.2}\\\\\text{Molality of }NaOH=0.551m[/tex]
Hence, the molality of NaOH in the solution is 0.551 m
