Question

Determine the weight of Na2SO4 dissolved in 700 grams of water if the solution has a concentration of 54.5% by weight?

Answer 1

Answer on Question #84361 – Chemistry – Other

Task:

Determine the weight of $\mathrm{Na_2SO_4}$ dissolved in 700 grams of water if the solution has a concentration of $54.5\%$ by weight?

Solution:

Mass percentage is the number of parts of mass of solute per hundred parts by mass of solution. If $m_x$ is the mass of solute $X$ and $m_s$ is the mass of solvent $S$, then

$$Mass \% = \frac{m_x}{m_x + m_s} * 100$$

Water $(\mathrm{H}_2\mathrm{O})$ is solvent.

$\mathrm{Na_2SO_4}$ is solute.

Then,

$$Mass \% = \frac{m(\mathrm{Na_2SO_4})}{m(\mathrm{Na_2SO_4}) + m(\mathrm{H_2O})} * 100;$$ $$Mass \% * [m(\mathrm{Na_2SO_4}) + m(\mathrm{H_2O})] = m(\mathrm{Na_2SO_4}) * 100;$$ $$54.5 * (x + 700) = x * 100;$$ $$54.5x + 38150 = 100x;$$ $$38150 = 100x - 54.5x;$$ $$38150 = 45.5x;$$ $$x = m(\mathrm{Na_2SO_4}) = 838.46g$$

Answer: 838.46 grams of $\mathrm{Na_2SO_4}$

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