Question

К 100 г раствора с w HNO3 6%,добавили раствором H2SO4 в результате в полученном растворе w HNO3 5%,w H2SO4 2,50.найти массовую долю h2SO4 в добавленном растворе

Answer 1

                     5%HNO3                   2.5%H2SO4
 
                                         6%HNO3  

                     3.5%H2SO4               1% HNO3
По методу "Крестa"  6-2,5= 3,5% Н2SO4 массовая доля добавленном растворе
                                    6-5= 1%HNO3

Answer 2

Problem Analysis

We are given a 100 g solution containing 6% HNO3. We then add a solution of H2SO4 to this solution, resulting in a final solution with 5% HNO3 and 2.50% H2SO4. We need to find the mass fraction of H2SO4 in the added solution.

Solution

Let's assume the mass of the added solution is x g.

The initial solution contains 6 g of HNO3 (6% of 100 g). After adding the solution, the final solution contains 5 g of HNO3 (5% of 100 g). Therefore, the amount of HNO3 that was added is 6 g - 5 g = 1 g.

We are also given that the final solution contains 2.50% H2SO4. Therefore, the amount of H2SO4 in the final solution is 2.50 g (2.50% of 100 g).

To find the mass fraction of H2SO4 in the added solution, we need to compare the mass of H2SO4 in the added solution to the total mass of the added solution.

Let's assume the mass fraction of H2SO4 in the added solution is y.

From the given information, we can set up the following equation:

(2.50 g)/(x g) = y

Simplifying the equation, we get:

y = (2.50 g)/(x g)

To find the value of y, we need to find the value of x.

We know that the initial solution has a mass of 100 g and the added solution has a mass of x g. Therefore, the total mass of the final solution is 100 g + x g.

We can set up another equation using the mass fractions of HNO3 in the initial and final solutions:

(1 g)/(100 g + x g) = 5%

Simplifying the equation, we get:

1 g = 5%(100 g + x g)

1 g = 0.05(100 g + x g)

1 g = 5 g + 0.05x g

0.05x g = 4 g

x g = 80 g

Now that we know the value of x, we can substitute it into the equation for y:

y = (2.50 g)/(80 g)

Simplifying the equation, we get:

y = 0.03125

Therefore, the mass fraction of H2SO4 in the added solution is 0.03125, or 3.125%.

Answer

The mass fraction of H2SO4 in the added solution is 3.125%.