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

Answer:

The mole fraction of NaCl in a solution prepared by dissolving 117 g of this in 1,11kg of water is 9.91 × 10-1

Explanation:

First of all you should know that:

Mole fraction solute = solute moles / solute moles + solvent moles

Mole fraction solvent = solvent moles / solute moles + solvent moles

and of course, you should know molar mass:

NaCl = 58,44 g/m

H2O = 18 g/m

For water you have 1, 11kg and you should convert to g for molar mass which is in g/m.

1,11kg * 1000 = 1110 g

1110 g / 18 g/m = 0,0162 moles

For NaCl you have 117 g, so the moles of solute are:

117 g / 58,44 g = 2,002 moles

Now, let's go to mole fraction solute.

solute moles / solute moles + solvent moles

2,002 moles / 2,002 moles + 0,0162 moles

2,002 moles / 2,0182 total moles = 0,991