Question

2. Сполучили розчини кухонної солі масою 150г з масовою часткою розчиненої речовини 12% і масою 250г з масовою часткою розчиненої речовини 15%. Обчисліть масову частку кухонної солі в отриманому розчині 3. Скільки грамів розчиненої речовини потрібно долити до розчину масою 40г з масовою часткою розчиненої речовини 5%, щоб отримати розчин з масовою часткою розчиненої речовини 10%? Поможіть ще є 20 минут

Answer 1

Ответ:

мамою надо совместить с солью и размешать будет растрвор

Answer 2

Calculation of Mass Fraction of Salt in the Solution

To calculate the mass fraction of salt in the solution, we need to consider the masses and mass fractions of the two solutions provided.

Let's denote the mass of the first solution (12% salt) as m1 and the mass of the second solution (15% salt) as m2.

Given: - Mass of the first solution, m1 = 150 g - Mass fraction of the salt in the first solution = 12% - Mass of the second solution, m2 = 250 g - Mass fraction of the salt in the second solution = 15%

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

Mass fraction of salt in resulting solution = (mass of salt in solution) / (total mass of solution)

Let's calculate the mass fraction of salt in the resulting solution step by step:

1. Calculate the mass of salt in the first solution: - Mass of salt in the first solution = (mass fraction of salt in the first solution) * (mass of the first solution) - Mass of salt in the first solution = 0.12 * 150 g

2. Calculate the mass of salt in the second solution: - Mass of salt in the second solution = (mass fraction of salt in the second solution) * (mass of the second solution) - Mass of salt in the second solution = 0.15 * 250 g

3. Calculate the total mass of the resulting solution: - Total mass of the resulting solution = (mass of the first solution) + (mass of the second solution)

4. Calculate the mass fraction of salt in the resulting solution: - Mass fraction of salt in resulting solution = (mass of salt in the first solution + mass of salt in the second solution) / (total mass of the resulting solution)

Let's calculate the mass fraction of salt in the resulting solution using the given values:

1. Mass of salt in the first solution = 0.12 * 150 g = 18 g 2. Mass of salt in the second solution = 0.15 * 250 g = 37.5 g 3. Total mass of the resulting solution = 150 g + 250 g = 400 g 4. Mass fraction of salt in resulting solution = (18 g + 37.5 g) / 400 g

Therefore, the mass fraction of salt in the resulting solution is 0.13875 or 13.875%.

Calculation of Mass of Substance to be Added

To calculate the mass of the substance that needs to be added to obtain a solution with a mass fraction of 10%, we need to consider the initial mass and mass fraction of the solution, as well as the desired mass fraction.

Given: - Mass of the initial solution = 40 g - Mass fraction of the salt in the initial solution = 5% - Desired mass fraction of the salt in the resulting solution = 10%

To calculate the mass of the substance to be added, we can use the following formula:

Mass of substance to be added = (desired mass fraction - initial mass fraction) / (1 - desired mass fraction) * mass of initial solution

Let's calculate the mass of the substance to be added step by step:

1. Calculate the mass of salt in the initial solution: - Mass of salt in the initial solution = (mass fraction of salt in the initial solution) * (mass of the initial solution) - Mass of salt in the initial solution = 0.05 * 40 g

2. Calculate the mass of the substance to be added: - Mass of substance to be added = (desired mass fraction - initial mass fraction) / (1 - desired mass fraction) * mass of the initial solution

Let's calculate the mass of the substance to be added using the given values:

1. Mass of salt in the initial solution = 0.05 * 40 g = 2 g 2. Mass of substance to be added = (0.10 - 0.05) / (1 - 0.10) * 40 g

Therefore, the mass of the substance that needs to be added to obtain a solution with a mass fraction of 10% is 8 g.

I hope this helps! Let me know if you have any further questions.