Question

QUESTION :-
It is desried to prepare 500 g of solution. with 10% urea in water. How much urea should we dissolve in how much volume of water?(density of water is 1 ml)

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Answer 1

Answer :-

50 grams of urea should be dissolved in 450 mL of water .

Explanation :-

We have :-

→ Mass of solution = 500 g

→ Concentration (w/w %) = 10 %

→ Density of water = 1 g/mL

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Mass of solute (urea) :-

Here, urea is solute and water is solvent . Let the required mass of urea be 'x' grams.

Putting values in the formula of mass by mass % concentration, we get :-

Mass of solute/Mass of solution × 100

⇒ (x/500) × 100 = 10

⇒ 100x = 5000

⇒ x = 5000/100

⇒ x = 50 g

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Mass of solvent :-

= Mass of solution - Mass of solute

= (500 - 50) g

= 450 g

Volume of solvent (water) :-

= Mass/Density

= 450/1

= 450 mL

Answer 2

Given :-

It is desried to prepare 500 g of solution. with 10% urea in water.

To Find :-

How much urea should we dissolve in how much volume of water?(density of water is 1 ml)

Solution :-

Let the mass of urea be 'a'

10 = a/Total weight of solution × 100

10 = a/500 × 100

10 = a/5 × 1

10 = a/5

10 × 5 = a

50 = a

Now

Remaining solution = 500 - 50

Remaining solution = 450 g

Density = Mass/Volume

1 = 450/V

1V = 450

V = 450 ml

Or,

Volume = Mass/Density

Volume = 450/1

Volume = 450 ml