Question

What mass of magnesium hydroxide would be required for the magnesium hydroxide to react to the equilvalence point with 558 mL of 3.18 M hyrdochloric acid?

Answer 1

Answer on Question #59736 – Chemistry– Other

Question:

What mass of magnesium hydroxide would be required for the magnesium hydroxide to react to the equivalence point with 558 mL of 3.18 M hydrochloric acid?

Answer:

The equivalence point, or stoichiometric point, of a chemical reaction is the point at which chemically equivalent quantities of acid and base have been mixed. In other words, the moles of acid are equivalent to the moles of base.

$$\mathrm{Mg(OH)}_2 + 4\mathrm{HCl} \rightarrow 2\mathrm{MgCl}_2 + 2\mathrm{H}_2\mathrm{O}$$

Molar concentration or molarity is defined as amount of solute per unit volume of solution:

$$c = \frac{n}{V} = \frac{m}{M * V}$$

Here, n is the amount of the HCl in moles, m is the mass of HCl, M is a molar mass of HCl (36.5 g/mol), V is the volume of solvent.

$$n = 3.18 * 558 / 1000 = 1.77 \text{ mol}$$

From the chemical equation we can calculate the required mass of magnesium hydroxide

x grams of magnesium hydroxide – 1.77 moles of HCl

58.32 g/mol (molar mass of magnesium hydroxide) – 4 moles of HCl

Then $x = 1.77 * 58.32 / 4 = 25.81$ g

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