What is the mole fraction of calcium chloride in 3.35 m CaCl₂(aq)? The molar mass of CaCl₂ is 111.0 g/mol and the molar mass of water is 18.02 g/mol. A) 0.000866 B) 0.0569 C) 0.271 D) 37.2 E) 59.2

Question

Quizplus · Accepted Answer

To find the mole fraction of calcium chloride, we need to first calculate the moles of calcium chloride present in the solution.

Moles of CaCl2 = (3.35 mol/L) x (1 L/1000 mL) x (111.0 g/mol) = 0.372 g

Next, we need to calculate the total moles of solute and solvent present in the solution:

Total moles = moles CaCl2 + moles H2O

The mass of 1 mL of water is 1 g, so the mass of 1000 mL (or 1 L) of water is 1000 g.

Mo1es of H2O = (1000 g) / (18.02 g/mol) = 55.49 mol

Total moles = 0.372 mol + 55.49 mol = 55.862 mol

Finally, we can calculate the mole fraction of CaCl2:

Mole fraction of CaCl2 = moles of CaCl2 / total moles 
= 0.372 mol / 55.862 mol 
= 0.00669

This is the same as 0.669%. However, we need to express this as a decimal, which gives us 0.000866. Therefore, the correct answer is B.

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