Question

what mass of sugar would have to be dissolved in 60 grams of water to yield a 25% solution?

Answer 1

Let mass of sugar required = S g

Mass of water = 60 g

Therefore, mass of solution = (S + 60) g

• Hence, % sugar in solution = {S/(S+60)} x100

Your concentration of sugar = 25 % w/w

Therefore, 25 = {S/(S+60)} x100

• 0.25 (S+60) = S

• 0.25S + 15 = S

• 0.75S = 15

On solving, S = 15/(0.75) = 20

Hence, by adding 20 g of sugar into 60 g water, your concentration of sugar is 25 %

Answer 2

Answer:

12 grams of sugar to be added.

Explanation:

Mass percentage of a solution = Mass of solute / Mass of solution * 100.

Let the mass of sugar be x.

Let the mass of solution be 60 + x.

:. 25% = x / 60 + x * 100.

=> 25 (60 + x) = 100 x.

=> 1500 + 25 x = 100 x.

=> 1500 = 100 x - 25 x.

=> 1500 = 75 x.

:. x = 1500 / 75.

=> 300 / 25.

=> 60 / 5.

=> 12 grams.

Therefore, 12 grams of sugar is needed with 60 grams of water to make 25% of sugar solution.