22 16 грамм карбонати натрийро дар чанд грамм об ҳал кардан лозим аст, то ки ҳиссаи массаи намак дар маҳлули ҳосилшуда 5%-ро ташкил диҳад?

Solution:

We are given that the mass of sodium carbonate (Na₂CO₃) is 16 g and it needs to be dissolved in water to form a 5% solution.

The formula for mass percentage is:

\[ \text{Mass %} = \frac{\text{mass of solute}}{\text{mass of solution}} \times 100 \]

In this case, the solute is Na₂CO₃ and the solution is the mixture of Na₂CO₃ and water.

Mass of solute = 16 g.

Mass percentage = 5%.

Let the mass of the solution be \( m_{\text{solution}} \).

\[ 5 = \frac{16 \text{ g}}{m_{\text{solution}}} \times 100 \]

Now, solve for \( m_{\text{solution}} \):

\[ m_{\text{solution}} = \frac{16 \text{ g} \times 100}{5} = 16 \text{ g} \times 20 = 320 \text{ g} \]

The mass of the solution is 320 g. The mass of the solution is the sum of the mass of the solute (Na₂CO₃) and the mass of the solvent (water).

\[ m_{\text{solution}} = m_{\text{solute}} + m_{\text{solvent}} \]

\[ 320 \text{ g} = 16 \text{ g} + m_{\text{water}} \]

Now, solve for the mass of water (\( m_{\text{water}} \)):

\[ m_{\text{water}} = 320 \text{ g} - 16 \text{ g} = 304 \text{ g} \]

Therefore, 304 grams of water are needed.

Answer: 304 грамм