Calculate the mass of sodium hydroxide, which is required to prepare a 20 g alkali solution, if the mass fraction of dissolved sodium hydroxide is 10%
The mass fraction of a substance in a solution is equal to the mass of the solute divided by the mass of the solution
w (NaOH) = m (NaOH) / mp-pa
From the formula we get m (NaOH) = w (NaOH) * mr-pa.
We express the mass fraction of sodium hydroxide in fractions, for this 10% / 100% = 0.1.
m (NAOH) = 0.1 * 20g = 2g
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