Question

Помогите дам 30 баллов. К 45 г воды добавили 15 г соли.Вычислите массовую долю вещества в растворе.

Answer 1

Ищем массу р-р
45+15=60
Ищем долю в-ва

15/60*100%=25%

Массовая доля соли= 25%

Answer 2

Calculation of Mass Fraction in Solution

To calculate the mass fraction of a substance in a solution, we need to know the masses of both the solute (the substance being dissolved) and the solvent (the substance doing the dissolving).

In this case, we have 45 grams of water (the solvent) and 15 grams of salt (the solute). To find the mass fraction of the salt in the solution, we can use the following formula:

Mass Fraction = (Mass of Solute / Total Mass of Solution) x 100%

Let's substitute the values into the formula:

Mass of Solute = 15 grams Total Mass of Solution = 45 grams + 15 grams = 60 grams

Mass Fraction = (15 grams / 60 grams) x 100%

Now, let's calculate the mass fraction:

Mass Fraction = (0.25) x 100% = 25%

Therefore, the mass fraction of the salt in the solution is 25%.

Please note that the calculation assumes that the volume of the solution remains constant and that the density of the solution is the same as that of water.