Dissolve 50 g of the same salt in 500 g of 25% sodium nitrate solution. Determine the mass fraction of salt in the new solution.

1. Given: 500 g of a 25% solution. Let’s find the mass of the dissolved salt by the formula:

m (salt) = m (solution) * w (solution) / 100% = 500 * 25/100 = 125 g

2. Given: 50 g of the same salt was added to the solution. Let’s find the total mass of salt:

125 + 50 = 175 g

3. Find the total mass of the solution:

500 + 50 = 550 g

4. Let’s calculate the mass fraction of salt in the resulting solution by the formula:

w (solution) = m (salt) * 100% / m (solution) = 175 * 100/550 = 31.8%.