A solution is obtained by mixing 300 g of 25% solution and 400 g of 40% solution by mass. Calculate the mass percentage of the resulting solution

Explanation

To calculate the mass percentage of the resulting solution obtained by mixing 300 g of a 25% solution and 400 g of a 40% solution, we can follow these steps:

### Step 1: Calculate the total mass of the resulting solution.
The total mass of the solution is the sum of the masses of the two solutions being mixed.

\[ \text{Total mass} = 300 \, \text{g} + 400 \, \text{g} = 700 \, \text{g} \]

### Step 2: Calculate the mass of the solute in each solution.
1. For the 25% solution:
\[ \text{Mass of solute} = \text{mass of solution} \times \left(\frac{\text{percentage}}{100}\right) = 300 \, \text{g} \times \left(\frac{25}{100}\right) = 75 \, \text{g} \]

2. For the 40% solution:
\[ \text{Mass of solute} = \text{mass of solution} \times \left(\frac{\text{percentage}}{100}\right) = 400 \, \text{g} \times \left(\frac{40}{100}\right) = 160 \, \text{g} \]

### Step 3: Calculate the total mass of the solute.
Now, we can find the total mass of the solute by adding the masses of the solute from both solutions.

\[ \text{Total mass of solute} = 75 \, \text{g} + 160 \, \text{g} = 235 \, \text{g} \]

### Step 4: Calculate the mass percentage of the resulting solution.
The mass percentage of the solute in the resulting solution can be calculated using the formula:

\[ \text{Mass percentage} = \left(\frac{\text{mass of solute}}{\text{total mass of solution}}\right) \times 100 \]

Substituting the values we have:

\[ \text{Mass percentage} = \left(\frac{235 \, \text{g}}{700 \, \text{g}}\right) \times 100 \approx 33.57\% \]

### Final Answer:
Thus, the mass percentage of the resulting solution is approximately **33.57%**.

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