Chemistry, asked by rimzimchauhan11, 7 months ago

100g of solution of urea in water has 10 g of urea (60g/mol) . find the molality of solution​

Answers

Answered by nethrasri20
0

Answer:

2.05 M

Explanation:

Molarity is defined as the number of moles of solute dissolved in per litre of solution.

Molarity, M=

V

n

n=number of moles of solute=mass/molar mass

V=volume of solution

mass of urea (NH

2

CONH

2

)=120g

Molar mass of urea= 60g/mol

Mass of water=1000g

Density of solution. ρ=1.15 g/mL

n=120/60=2mol

m

solution

=m

solute

+m

solvent

(∵ Law of conservation of mass)

ρ

solution

×V

solution

=120+1000 (using m=ρ.V)

1.15×V

solution

=1120

V

solution

=974mL=0.974L

thus M=

V

n

=

0.974

2

=2.05M

Molarity of the solution is 2.05M

Answered by ItzAwesomeGirl
3

\huge\color{red}{A}\color{blue}{N}\color{orange}{S}\color{green}{W}\color{pink}{E}\color{red}{R}The molality of the solution is 1.84 m

Explanation :

Step 1 : Find moles of solute.

The solute in this case is urea. Let us find moles of urea.

mol =\frac{grams}{Molar Mass}mol=

MolarMass

grams

Molar mass of urea is 60.1 g/mol

We have 10 grams of urea.

Let us plug in these values to find moles.

mol =\frac{10g}{60.1g/mol} = 0.166 molmol=

60.1g/mol

10g

=0.166mol

We have 0.166 mol urea.

Step 2 : Find mass of solvent

Water is solvent here .

The mass of solution is given as 100 g.

Mass of solution = mass of solute + mass of solvent

100 g = 10 g + mass of solvent

mass of solvent = 100 g - 10 g = 90 g = 0.09 kg

Step 3 : Use molality formula

The molality of a solution is calculated using following formula

m = \frac{(mol) Solute}{(kg) Solvent}m=

(kg)Solvent

(mol)Solute

molality =\frac{0.166 mol}{0.09 kg}molality=

0.09kg

0.166mol

molality = 1.84mmolality=1.84m

The molality of the given solution is 1.84 m

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