Question

Раствор хлорида железа (III) массой 200 г и массовой долей10% смешали с гидроксидом натрия. Вычислите массу образовавшегося осадка?

Answer 1

Calculation of the Mass of the Precipitate

To calculate the mass of the precipitate formed when 200 g of iron(III) chloride with a mass fraction of 10% is mixed with sodium hydroxide, we need to consider the balanced chemical equation for the reaction between iron(III) chloride and sodium hydroxide.

The balanced chemical equation for the reaction is as follows: FeCl3 + 3NaOH → Fe(OH)3 + 3NaCl

From the balanced equation, we can see that one mole of iron(III) chloride reacts with three moles of sodium hydroxide to produce one mole of iron(III) hydroxide and three moles of sodium chloride.

To calculate the mass of the precipitate, we need to determine the limiting reactant. The limiting reactant is the reactant that is completely consumed in the reaction and determines the maximum amount of product that can be formed.

To find the limiting reactant, we need to compare the number of moles of each reactant present. We can calculate the number of moles of iron(III) chloride using its molar mass and the given mass:

Number of moles of FeCl3 = Mass of FeCl3 / Molar mass of FeCl3

The molar mass of FeCl3 can be calculated by adding the atomic masses of iron (Fe) and three chlorine (Cl) atoms:

Molar mass of FeCl3 = Atomic mass of Fe + (3 * Atomic mass of Cl)

Now, we can calculate the number of moles of FeCl3:

Number of moles of FeCl3 = 200 g / (Atomic mass of Fe + (3 * Atomic mass of Cl))

To determine the limiting reactant, we also need to calculate the number of moles of sodium hydroxide. The molar mass of NaOH can be calculated by adding the atomic masses of sodium (Na), oxygen (O), and hydrogen (H):

Molar mass of NaOH = Atomic mass of Na + Atomic mass of O + Atomic mass of H

Now, we can calculate the number of moles of NaOH:

Number of moles of NaOH = (Number of moles of FeCl3) * 3

Since the reaction ratio between FeCl3 and NaOH is 1:3, the number of moles of NaOH is three times the number of moles of FeCl3.

Next, we need to determine the limiting reactant by comparing the number of moles of FeCl3 and NaOH. The reactant with the smaller number of moles is the limiting reactant.

Once we have identified the limiting reactant, we can calculate the number of moles of the precipitate formed using the stoichiometry of the balanced equation. In this case, the precipitate is iron(III) hydroxide (Fe(OH)3).

Finally, we can calculate the mass of the precipitate using the number of moles of the precipitate and its molar mass.

Please note that the atomic masses of the elements can be found in the periodic table.

Let's calculate the mass of the precipitate step by step.