In 120 g of a solution with a mass fraction of salt of 7%, 30 g of water was added.
| September 9, 2021 | education
In 120 g of a solution with a mass fraction of salt of 7%, 30 g of water was added. Determine the mass fraction of salt in the resulting solution.
From the known data, we find the mass of salt in the solution:
w = m (salt) / m (solution) * 100% = 7%
m (salt) / 120 = 0.07. Hence we find that m (salt) = 8.4 g.
Now we will find the mass fraction of this salt after adding 30 g of water:
w = 8.4 / (120 + 30) = 8.4 / 150 = 0.056.
Consequently, the mass fraction of salt in the solution is 5.6%.
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