What is the molality of a semimolar Nacl solution if the density of the solution is 1.16g cm^3?

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Definition of Molality:
Molality is a measure of the concentration of a solute in a solution, expressed in moles of solute per kilogram of solvent. It is denoted by the symbol 'm' and is calculated using the formula:

Molality (m) = moles of solute / mass of solvent (in kg)

Given Information:
- NaCl solution with a density of 1.16 g/cm^3
- We need to find the molality of the solution

Calculating Mass of Solvent:
To calculate the mass of the solvent, we need to know the volume of the solution and the density of the solution. However, this information is not provided in the given question. Therefore, we cannot directly calculate the mass of the solvent.

Alternative Approach:
Since we are given the density of the solution, we can assume a convenient volume for the solution and calculate the mass of the solvent using the density formula:

Density = mass / volume

Assuming a Volume:
Let's assume a volume of 1 L (1000 cm^3) for the solution. This is a common assumption in such calculations.

Calculating Mass of Solvent:
Using the given density, we can calculate the mass of the solution:

Mass of solution = density * volume = 1.16 g/cm^3 * 1000 cm^3 = 1160 g

Calculating Moles of Solute:
The concentration of NaCl in the solution is semimolar, which means there is 0.5 moles of NaCl per liter of solution. Therefore, in 1 L of solution, there are 0.5 moles of NaCl.

Converting Mass of Solvent to Kilograms:
To calculate molality, we need the mass of the solvent in kilograms. Therefore, we convert the mass of the solvent from grams to kilograms by dividing by 1000:

Mass of solvent = 1160 g / 1000 = 1.16 kg

Calculating Molality:
Finally, we can calculate the molality using the formula:

Molality (m) = moles of solute / mass of solvent

Molality (m) = 0.5 moles / 1.16 kg ≈ 0.431 mol/kg

Conclusion:
The molality of the semimolar NaCl solution, assuming a volume of 1 L, is approximately 0.431 mol/kg.

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