Question

В реакцию с хлоридной кислотой вступило 12г магния. Какое количество газа выделится при этом (в молях) и какая масса (в граммах) полученой соли.

Answer 1

Mg + 2HCl = MgCl2 + H2
n(H2) = n(Mg) = m(Mg)/M(Mg) = 12/24 = 0,5 моль
n(MgCl2) = n(Mg) = 0,5 моль
m(MgCl2) = nxM = 0,5x95 = 47,5 г

Answer 2

Reaction with Hydrochloric Acid

When 12g of magnesium reacts with hydrochloric acid, the following reaction occurs:

Magnesium reacts with hydrochloric acid to produce magnesium chloride and hydrogen gas.

The balanced chemical equation for this reaction is:

Mg + 2HCl → MgCl2 + H2

Calculation of Gas Produced

To calculate the amount of gas produced in moles, we can use the stoichiometry of the reaction. From the balanced chemical equation, we can see that 1 mole of magnesium reacts with 2 moles of hydrochloric acid to produce 1 mole of hydrogen gas.

Given that the molar mass of magnesium is approximately 24.305 g/mol and the molar mass of hydrogen is approximately 1.008 g/mol, we can calculate the moles of hydrogen gas produced.

The molar mass of magnesium chloride is approximately 95.211 g/mol.

Using the molar mass of magnesium and the stoichiometry of the reaction, we can calculate the moles of hydrogen gas produced:

Moles of hydrogen gas = (mass of magnesium / molar mass of magnesium) * (1 mole of H2 / 1 mole of Mg)

Moles of hydrogen gas = (12g / 24.305 g/mol) * (1 mole / 1 mole) = 0.493 moles of H2

Calculation of Mass of Magnesium Chloride Produced

To calculate the mass of magnesium chloride produced, we can use the stoichiometry of the reaction and the molar mass of magnesium chloride.

Using the stoichiometry of the reaction, we know that 1 mole of magnesium produces 1 mole of magnesium chloride.

The mass of magnesium chloride produced can be calculated as follows:

Mass of magnesium chloride = (moles of magnesium / 1) * (molar mass of magnesium chloride)

Mass of magnesium chloride = 0.493 moles * 95.211 g/mol = 46.9g

Therefore, when 12g of magnesium reacts with hydrochloric acid, approximately 0.493 moles of hydrogen gas are produced, and the mass of magnesium chloride obtained is approximately 46.9g.