To 800 g of a 50% solution was added 200 g of water. The percentage of salt in the new solution has become …

1. Let’s calculate the mass of the salt contained in the initial solution:

m (salt) = w (salt) * m (solution) = 0.5 * 800 = 400 g;

2. find the mass of the solution obtained by adding a portion of water:

mpol (solution) = mout (solution) + madd (H2O) = 800 + 200 = 1000 g;

3. Determine the percentage of salt concentration in the resulting solution:

wnew (salt) = m (salt): mpol (solution) = 400: 1000 = 0.4 or 40%.

Answer: 40%.