Question

6 grams of urea (NH2CONH2) dissloved in 180 grams of H20,what is molefraction of
Urea and Water ?​

Answer 1

Answer:

$\bigstar{\bold{Mole\:fraction\:of\:urea=9.9\times 10^{-3}}}$

$\bigstar{\bold{Mole\:fraction\:of\:water=0.99}}$

Explanation:

$\Large{\underline{\underline{\rm{Given:}}}}$

• Mass of urea (NH₂CONH₂) = 6 gm
• Mass of water (H₂O) = 180 gm

$\Large{\underline{\underline{\rm{To\:Find:}}}}$

• Molefraction of urea and water

$\Large{\underline{\underline{\rm{Solution:}}}}$

➸ First we have to find the number of moles of urea and water

➸ Number of moles of a compund is given by,

    Number of moles = Given mass/Molar mass

➸ Molar mass of NH₂CONH₂ = 14 +  2 × 1 + 12 + 16 + 14 + 2 × 1

    Molar mass of NH₂CONH₂ = 14 + 2 + 12 + 16 + 14 + 2

   Molar mass of NH₂CONH₂ = 60 g

➸ Molar mass of H₂O = 2 × 1 + 16

    Molar mass of H₂O = 18 g

➸ Number of moles of NH₂CONH₂ = 6/60

    Number of moles of NH₂CONH₂ = 0.1 moles

➸ Number of moles of H₂O = 180/18

    Number of moles of H₂O = 10 moles

➸ Now mole fraction of a substance in a solution is given by,

   Mole fraction = Number of moles of component/Total number of moles in the solution.

➸ Mole fraction of urea = 0.1/(0.1 + 10)

    Mole fraction of urea = 0.1/10.1

    Mole fraction of urea = 9.9 × 10⁻³

    $\boxed{\bold{Mole\:fraction\:of\:urea=9.9\times 10^{-3}}}$

➸ Mole fraction of water = 10/0.1 + 10

    Mole fraction of water = 10/10.1

    Mole fraction of water = 0.99

    $\boxed{\bold{Mole\:fraction\:of\:water=0.99}}$

$\Large{\underline{\underline{\rm{Notes:}}}}$

➸ Number of moles of a substance is given by,

    Number of moles = Given mass/Molar mass

➸ Mole fraction of a component present in a solution

    Mole fraction = number of moles of component/total number of moles present in the solution.