Question

Calculate the mole fraction of NaCl in a solution prepared by dissolving 117 g NaCl in 1.11 kg H2O.

1.12 × 10-2

6.29 × 10-2

1.57 × 10-2

9.91 × 10-1

3.15 × 10-2

Answer 1

The mole fraction of NaCl in the solution is 3.15 × 10-2.

Step-by-step explanation:

The mole fraction of NaCl in a solution prepared by dissolving 117 g NaCl in 1.11 kg H2O can be calculated by dividing the moles of NaCl by the total moles of solute and solvent. First, we convert the mass of NaCl to moles using its molar mass. Then, we calculate the moles of water by dividing its mass by its molar mass. Finally, we divide the moles of NaCl by the sum of moles of NaCl and moles of water to get the mole fraction of NaCl in the solution.

Given:

• Mass of NaCl = 117 g
• Mass of H2O = 1110 g (1.11 kg)
• Molar mass of NaCl = 58.44 g/mol
• Molar mass of H2O = 18.02 g/mol

Step 1: Convert mass of NaCl to moles:

Moles of NaCl = (mass of NaCl / molar mass of NaCl) = (117 g / 58.44 g/mol) = 2 moles

Step 2: Convert mass of H2O to moles:

Moles of H2O = (mass of H2O / molar mass of H2O) = (1110 g / 18.02 g/mol) = 61.55 moles

Step 3: Calculate mole fraction of NaCl:

Mole fraction of NaCl = (moles of NaCl / (moles of NaCl + moles of H2O)) = (2 moles / (2 moles + 61.55 moles)) = 3.15 × 10-2