Question

К 380 г 15% раствора соли добавили 120 г воды. Какова новая массовая доля растворённого вещества в полученном растворе

Answer 1

Если масса раствора равна 380г, а массовая доля соли в нем 15%, то масса соли в растворе равна:

380 - 100%

х - 15%

х=380*15/100=57г

Дальше, когда добавили 120 г воды в раствор, массовая доля соли меняется, но его масса остается одинаковой.

Масса раствора=380+120=500г

500г - 100%

57 г - у%

у=57*100/500=11.4

Массовая доля соли равна 11.4%

Answer 2

Calculation of the New Mass Fraction of the Solution

To calculate the new mass fraction of the dissolved substance 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 (salt + water) = 380 g - Initial mass fraction of the dissolved substance (salt) = 15% - Mass of water added = 120 g

To find the new mass fraction of the dissolved substance in the resulting solution, we can follow these steps:

1. Calculate the mass of the dissolved substance (salt) in the initial solution: - Initial mass of the dissolved substance = Initial mass of the solution * Initial mass fraction of the dissolved substance - Initial mass of the dissolved substance = 380 g * 0.15 = 57 g

2. Calculate the total mass of the resulting solution: - Total mass of the resulting solution = Initial mass of the solution + Mass of water added - Total mass of the resulting solution = 380 g + 120 g = 500 g

3. Calculate the new mass fraction of the dissolved substance in the resulting solution: - New mass fraction of the dissolved substance = Mass of the dissolved substance / Total mass of the resulting solution - New mass fraction of the dissolved substance = 57 g / 500 g ≈ 0.114

Therefore, the new mass fraction of the dissolved substance in the resulting solution is approximately 0.114 or 11.4%.

Please note that the calculations provided above are based on the information given and may not take into account other factors or considerations that could affect the final result.