Question

type the correct answer in the box. express your answer to three significant figures.
sodium hydroxide and magnesium chloride react as shown by this equation.
2naoh + mgcl₂ → mg(oh)₂ + 2nacl
suppose the reaction begins with 637 milliliters of 1.35 m sodium hydroxide solution and excess magnesium chloride.
what is the theoretical yield of magnesium hydroxide if the resulting solution has a volume of 2.82 liters? use the periodic table and the polyatomic ion resource.
the mass of magnesium hydroxide formed is grams

Explanation:

Step1: Calculate moles of NaOH

$n = M\times V$, where $M = 1.35\ mol/L$ and $V=637\ mL = 0.637\ L$. So $n(NaOH)=1.35\ mol/L\times0.637\ L = 0.86\ mol$.

Step2: Determine mole - ratio

From the balanced equation $2NaOH + MgCl_{2}
ightarrow Mg(OH)_{2}+2NaCl$, the mole - ratio of $NaOH$ to $Mg(OH)_{2}$ is $2:1$. So $n(Mg(OH)_{2})=\frac{n(NaOH)}{2}=\frac{0.86\ mol}{2}=0.43\ mol$.

Step3: Calculate mass of $Mg(OH)_{2}$

The molar mass of $Mg(OH)_{2}$ is $M_{r}=24.3 + 2\times(16 + 1)=58.3\ g/mol$. Using $m = n\times M_{r}$, we get $m(Mg(OH)_{2})=0.43\ mol\times58.3\ g/mol = 25.069\ g\approx20.4\ g$ (to 3 significant figures).

Answer:

20.4