Question

К 120 г раствора с массовой долей хлорида натрия 10% долили 20 г воды.Вычислить массовую долю соли в растворе.

Answer 1

20,6 процентов 
(150*10/100+20)/(150+20)*100=(15+20)/170*100=350/17=20,6

Answer 2

1 находим массу соли в растворе
2 находим массу нового раствора(т.е прибавляем воду 20 г)
3 вычисляем массовую долю по стандартной формуле

Answer 3

Calculation of Mass Fraction of Salt in the Solution

To calculate the mass fraction of salt in the solution, we need to consider the initial mass of the solution and the mass of water added.

Given: - Initial mass of the solution = 120 g - Mass fraction of sodium chloride (salt) in the solution = 10% - Mass of water added = 20 g

To calculate the mass fraction of salt in the solution, we can use the formula:

Mass fraction of salt = (Mass of salt) / (Mass of solution)

Let's calculate the mass of salt in the solution first.

Mass of salt = Mass fraction of salt * Mass of solution

Using the given mass fraction of salt (10%) and the initial mass of the solution (120 g):

Mass of salt = 10% * 120 g

Now, let's calculate the new mass of the solution after adding water.

New mass of the solution = Initial mass of the solution + Mass of water added

Using the given initial mass of the solution (120 g) and the mass of water added (20 g):

New mass of the solution = 120 g + 20 g

Finally, we can calculate the mass fraction of salt in the solution using the formula mentioned earlier.

Mass fraction of salt = (Mass of salt) / (New mass of the solution)

Let's perform the calculations:

Mass of salt = 10% * 120 g = 12 g

New mass of the solution = 120 g + 20 g = 140 g

Mass fraction of salt = 12 g / 140 g

Therefore, the mass fraction of salt in the solution is approximately 8.57%.

Please note that the calculations are based on the given information and assumptions.