20% w/v of aqueous solution of urea having density 1.1gm/ml. Find mole fraction of urea. ?

Question

Answer

Calculation of Mole Fraction of Urea

To calculate the mole fraction of urea in a 20% w/v aqueous solution, we need to first calculate the mass of urea present in 1000 ml of solution.

Calculation of Mass of Urea

Therefore, in 1000 ml (1 L) of solution, the mass of urea will be 20 x 10 = 200 g.

Calculation of Moles of Urea

Number of moles of urea present in 200 g can be calculated as: moles = mass / molar mass = 200 / 60.06 = 3.33 mol.

Calculation of Total Mass of Solution

Therefore, the total mass of the solution can be calculated as: mass = volume x density = 1000 x 1.1 = 1100 g.

Calculation of Mole Fraction of Urea

Mole fraction of urea can be calculated as: mole fraction of urea = moles of urea / total moles of solution.

Number of moles of water present in the solution can be calculated as: moles of water = mass of water / molar mass of water.

Mass of water present in the solution can be calculated as: mass of water = total mass of solution - mass of urea = 1100 - 200 = 900 g.

Number of moles of water present in the solution can be calculated as: moles of water = 900 / 18.02 = 49.94 mol.

Total moles of solution can be calculated as: total moles = moles of urea + moles of water = 3.33 + 49.94 = 53.27 mol.

Therefore, mole fraction of urea can be calculated as: mole fraction of urea = 3.33 / 53.27 = 0.063.

Conclusion

The mole fraction of urea in a 20% w/v aqueous solution is 0.063.

Answer

Answer

0.0625