An additional 50 g of NaOH was added to 250 g of a 30% NaOH solution. Determine the mass fraction

An additional 50 g of NaOH was added to 250 g of a 30% NaOH solution. Determine the mass fraction of NaOH in the resulting solution.

Given:
m p1 (NaOH) = 250 g
w (NaOH) = 30% = 0.3
m2 (NaOH) = 50 g
To find:
m р3 (NaOH) = 250 g + 50 g = 300 g
m in1 (NaOH) = w * m p1 = 0.3 * 250 g = 75 g
m в3 (NaOH) = 50 g + 75 g = 125 g
w3 (NaOH) = m b3 / m p3 * 100% = 125 g / 300 g * 100% = 41.66%
Answer: 41.66%