Chemistry, asked by mydhilipremraj02, 8 months ago

an aqueous solution of urea is found to boil at 100.52°C given for water is 0.52kkgmol-1 the mole fraction of urea in solution is?​

Answers

Answered by hamzaiqbal0335
9

Explanation:

it means one mole of urea is dissolved in one of(55.5moles)of water then mole fraction is

no. of moles of urea/total moles of mixture

1/56.5=.0177

Answered by anjali13lm
1

Answer:

The urea's mole fraction in the solution measured is 0.017.

Explanation:

Given,

The molal elevation constant, K_{b} = 0.52K kgmol^{-1}

The boiling temperature, T_{b} = 100\textdegree C

The mole fraction of urea =?

Firstly, we have to calculate the molality from the relation given below:

  • \Delta T = K_{b}\times m    -------equation (1)

Here,

  • \Delta T = The change in the boiling point
  • K_{b} = The molal elevation constant
  • m = Molality

Also,

  • \Delta T = T_{b} - T

Here,

  • T = The boiling temperature of water = 100\textdegree C

Therefore,

  • \Delta T = 100.52 - 100 = 0.52\textdegree C

After putting this value in equation (1), we get:

  • 0.52 = 0.52\times m
  • m = 1 molal

As we know,

  • 1 molal means 1 mole of solute on 1000g of solvent.

Therefore, there is one mole of urea (n_{u}).

As given, the solvent is water and the mass of the solvent is 1000g as calculated above.

Also, the molar mass of water = 18g/mol

Now,

  • The number of moles of water, n_{w} = \frac{Mass}{Molar mass} = \frac{1000}{18} = 55.55mol

Thus,

  • The mole fraction of urea = \frac{n_{u} }{n_{u}+n_{w}  } = \frac{1}{1+ 55.55} = \frac{1}{56.55} = 0.017

Hence, the urea's mole fraction in the solution = 0.017.

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