Solutions: Percentage by mass (1931)

, por F_y_Q

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Make a solution by mixing 22 g of sugar and 240 mL of milk. Determine the percentage by mass of this solution. How much sugar is needed to prepare 500 g of solution with the same concentration?

Average density of milk is 1.03\ g\cdot mL^{-1}.

P.-S.

The mass of milk used for the mixture is:

240\ \cancel{mL}\cdot \frac{1.03\ g}{1\ \cancel{mL}} = \color[RGB]{0,112,192}{\bf 247.2\ g}

The total mass of the solution is:

m_T = m_S + m_d = (22 + 247.2)\ g\ \to\ m_D = \color[RGB]{0,112,192}{\bf 269.2\ g}

The mass percentage is:

\%(m) = \frac{m_S}{m_T}\cdot 100 = \frac{22\ \cancel{g}}{269.2\ \cancel{g}}\cdot 100 = \fbox{\color[RGB]{192,0,0}{\bf 8.17\ \%}}


The obtained result indicates that you need 8.17 g of sugar to prepare 100 g of solution:

500\ \cancel{g\ D}\cdot \frac{8.17\ g\ S}{100\ \cancel{g\ D}} = \fbox{\color[RGB]{192,0,0}{\bf 40.9\ g\ S}}