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You prepare a solution by dissolving 50.4 g sucrose (C₁₂H₂₂O₁₁) in 0.332 kg of water. The final volume of the solution is 355 mL. Calculate the concentration of the solution in each unit.

a. Molarity
b. Molality
c. Percent by mass
d. Mole fraction
e. Mole percent

User Pajaja
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1 Answer

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Final answer:

The concentration of a sucrose solution is 0.415 M in molarity, 0.4437 m in molality, 13.18% by mass, 0.0079 mole fraction, and 0.79% mole percent.

Step-by-step explanation:

To calculate the concentration of a sucrose solution in different units, we must first determine the amount of sucrose in moles. Sucrose has a molar mass of approximately 342.30 g/mol.

To find the molarity, divide moles of sucrose by the volume of the solution in liters:

Number of moles = 50.4 g / 342.30 g/mol = 0.1473 mol

Volume of solution = 355 mL = 0.355 L

Molarity (M) = 0.1473 mol / 0.355 L = 0.415 M

For molality, calculate moles of sucrose per kilogram of water:

Molality (m) = 0.1473 mol / 0.332 kg = 0.4437 m

The percent by mass is found by dividing the mass of solute by the total mass of the solution and multiplying by 100:

Percent by mass = (50.4 g / (50.4 g + 332 g)) * 100 = 13.18%

To calculate the mole fraction of sucrose, divide moles of sucrose by total moles in solution:

Total moles = Moles of water + Moles of sucrose

Moles of water = 332 g / 18.015 g/mol = 18.43 mol

Mole fraction of sucrose (χsucrose) = 0.1473 mol / (18.43 mol + 0.1473 mol) = 0.0079

Finally, to find the mole percent, multiply the mole fraction by 100:

Mole percent = 0.0079 * 100 = 0.79%

User Sruthi
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