Question

До розчину що містить 40 г солі додали 200 г води після чого його консентрація зменшилась на 10% . Скільки води містить розчин і я кою була його концентрація

Answer 1

Нехай розчин містить х г води. Тоді концентрація солі в ньому буде дорівнювати 40:(х+40). Після того, як додали 200 г води у розчині стало х+200 г води, а концентрація солі в ньому 40:(х+240). Маємо рівняння
$\frac{40}{x+40}-\frac{40}{x+240}=0.1;\\ (x+240)(x+40)=400(240-40);\\ x^2+280x+9600=80000;\\ x^2+280x-70400=0;\\ D'=19600+70400=90000=(300)^2;\\ x=-140+300=160$
Отже, у розчині було 160 г води, а концентрація - 40:(40+160)=0.2=20%

Answer 2

Calculation of Water Content and Concentration Change in Solution

To calculate the water content and concentration change in the solution, we need to follow these steps:

Step 1: Calculate the initial concentration of the solution. Step 2: Determine the final concentration of the solution after the addition of water. Step 3: Calculate the amount of water added to the solution. Step 4: Calculate the final water content in the solution.

Let's go through each step in detail.

Step 1: Calculate the initial concentration of the solution

The initial concentration of the solution can be calculated using the formula:

Initial Concentration = (Mass of solute / Total mass of solution) x 100%

In this case, the mass of the solute (salt) is given as 40 g, and the total mass of the solution is the sum of the mass of the solute and the mass of the solvent (water), which is 40 g + 200 g = 240 g.

Using the formula, we can calculate the initial concentration as follows:

Initial Concentration = (40 g / 240 g) x 100% = 16.67%

Step 2: Determine the final concentration of the solution after the addition of water

The problem states that the concentration of the solution decreased by 10% after the addition of water. To determine the final concentration, we need to subtract 10% from the initial concentration.

Final Concentration = Initial Concentration - (Initial Concentration x 10%)

Substituting the initial concentration value into the formula, we can calculate the final concentration as follows:

Final Concentration = 16.67% - (16.67% x 10%) = 15%

Step 3: Calculate the amount of water added to the solution

To calculate the amount of water added to the solution, we need to subtract the initial mass of water from the final mass of the solution.

The initial mass of water is given as 200 g, and the final mass of the solution is the sum of the initial mass of water and the mass of the solute, which is 200 g + 40 g = 240 g.

Therefore, the amount of water added to the solution is:

Amount of Water = Final Mass of Solution - Initial Mass of Water = 240 g - 200 g = 40 g

Step 4: Calculate the final water content in the solution

To calculate the final water content in the solution, we need to divide the amount of water added by the final mass of the solution and multiply by 100%.

Final Water Content = (Amount of Water / Final Mass of Solution) x 100%

Substituting the values into the formula, we can calculate the final water content as follows:

Final Water Content = (40 g / 240 g) x 100% = 16.67%

Therefore, the final water content in the solution is 16.67%.

To summarize: - The solution contains 40 g of salt. - The solution contains 200 g of water. - The final water content in the solution is 16.67%. - The final concentration of the solution is 15%.

Please let me know if there's anything else I can help you with!