Question

The mole fraction of NaCl in an

aqueous solution is 0.132. What is
the weight/weight percent of NaCl in
this solution?
Molar Mass
NaCl: 58.44 g/mol
H20: 18.016 g/mol
Hint: Remember to give your answer as a percent!

Answer 1

The weight/weight percent of NaCl in the solution, with a mole fraction of 0.132, can be calculated by converting moles to grams and then finding the percentage by mass. The calculated weight/weight percentage of NaCl is 33.02%.

Step-by-step explanation:

To find the weight/weight percent of NaCl in the solution, given its mole fraction is 0.132, we first need to express the molar ratio in terms of mass. Considering the molar masses of NaCl and H2O, we can set up a proportion with the mole fraction formula:

• Mole fraction of NaCl = (moles of NaCl) / (moles of NaCl + moles of H2O)
• Assuming a total of 1 mole of solution, 0.132 = (moles of NaCl) / (1 mole of solution)
• Moles of NaCl = 0.132 moles

Next, convert moles of NaCl into grams using its molar mass:

• Mass of NaCl = 0.132 moles * 58.44 g/mol = 7.714 g

To find the mass of water, subtract the moles of NaCl from 1 mole:

• Moles of H2O = 1 mole - 0.132 moles = 0.868 moles
• Mass of H2O = 0.868 moles * 18.016 g/mol = 15.637 g

The mass of the solution is the sum of the mass of NaCl and the mass of H2O:

• Mass of solution = 7.714 g + 15.637 g = 23.351 g

Finally, to find the weight/weight percent of NaCl, divide the mass of NaCl by the total mass of the solution and multiply by 100:

• Weight/weight percent of NaCl = (7.714 g / 23.351 g) * 100 = 33.02%

Answer 2

The weight/weight percent(%w/w) of NaCl in solution : 33.03%

Further explanation

Given

Mole fraction of NaCl : 0.132

Required

The weight/weight percent of NaCl

Solution

1 mol solution : 0.132 mol NaCl + 0.868 mol H₂O

mass NaCl :

`\tt 0.132* 58.44 g/mol=7.714~g`

mass H₂O :

`\tt 0.868* 18.016~g/mol=15.64~g`

Total mass = 7.714 + 15.64 = 23.354 g

`\tt \%NaCl=(7.714)/(23.354)* 100\%=33.03\%`