Question

К 400 г раствора содержащего 18% хлорида калия добавили 500 мл воды. Определить массовую долю (в процентах) хлорида калия в полученном растворе

Answer 1

500 мл=500 г
масса KNO3
m=400 *0,18=72 г
добавили 500 г воды,но масса KNO3 не изменилась
400г+500г=900г
x=72г/900г*100%=8%
Ответ:8%

Answer 2

Calculation of Mass Fraction of Potassium Chloride in the Solution

To determine the mass fraction of potassium chloride in the solution, we need to consider the initial concentration of potassium chloride and the volume of water added.

Given: - Initial solution volume: 400 mL - Initial concentration of potassium chloride: 18% - Volume of water added: 500 mL

To calculate the mass fraction, we can use the formula:

Mass Fraction = (Mass of solute / Mass of solution) x 100%

First, let's calculate the mass of potassium chloride in the initial solution:

Mass of potassium chloride in the initial solution = Initial solution volume x Initial concentration of potassium chloride

Mass of potassium chloride in the initial solution = 400 mL x 18% = 72 g

Next, let's calculate the total mass of the solution after adding water:

Total mass of the solution = Mass of potassium chloride in the initial solution + Mass of water added

Total mass of the solution = 72 g + 500 mL (since the density of water is approximately 1 g/mL)

Now, we can calculate the mass fraction of potassium chloride in the solution:

Mass Fraction = (Mass of potassium chloride in the initial solution / Total mass of the solution) x 100%

Mass Fraction = (72 g / (72 g + 500 g)) x 100% = 12.59%

Therefore, the mass fraction of potassium chloride in the resulting solution is approximately 12.59%.

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