To a solution weighing 250 g, the mass fraction of salt in which is 10%, water was poured in a volume

To a solution weighing 250 g, the mass fraction of salt in which is 10%, water was poured in a volume of 150 ml. Taking the density of water equal to 1 g / ml, determine the mass fraction of salt in the resulting solution.

1. Let’s find the mass of salt:

m (salt) = ω (salt) * m (solution) = 0.1 * 250 = 25g.

2. It is known that the density of water is 1 g / ml. Then in this case m (H2O) = 150g.

3. Find the second mass of the solution:

m (second, solution) = m (solution) + m (H2O) = 250 + 150 = 400g.

4. Let’s find the mass fraction of salt:

ω (salt) = m (salt) / m (second, solution) = 25/400 = 0.0625 (6.25%).

Answer: ω (salt) = 6.25%.