Question

Смеси алюминия и меди массой 12Г обработали соляной кислотой .Выделившийся водород занял объем 7,4 л (н.у.).Определите массовую долю каждого металла в смеси в смеси.

Answer 1

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Answer 2

Calculation of Mass Fraction of Aluminum and Copper in the Mixture

To determine the mass fraction of aluminum and copper in the mixture, we need to use the information provided about the reaction with hydrochloric acid and the volume of hydrogen gas produced.

Given: - Mass of the mixture = 12 g - Volume of hydrogen gas produced = 7.4 L (at standard temperature and pressure)

To calculate the mass fraction of each metal, we can use the concept of stoichiometry and the ideal gas law.

The balanced chemical equation for the reaction between aluminum and copper with hydrochloric acid is:

2Al + 6HCl → 2AlCl3 + 3H2

From the equation, we can see that 2 moles of aluminum react with 6 moles of hydrochloric acid to produce 3 moles of hydrogen gas. Therefore, the mole ratio between aluminum and hydrogen is 2:3.

To find the number of moles of hydrogen gas produced, we can use the ideal gas law:

PV = nRT

Where: - P is the pressure (at standard temperature and pressure, it is 1 atm) - V is the volume of the gas (7.4 L) - n is the number of moles of the gas (to be determined) - R is the ideal gas constant (0.0821 L·atm/mol·K) - T is the temperature (at standard temperature and pressure, it is 273 K)

Rearranging the equation, we can solve for n:

n = PV / RT

Substituting the given values:

n = (1 atm) * (7.4 L) / (0.0821 L·atm/mol·K * 273 K)

n ≈ 0.32 moles

Since the mole ratio between aluminum and hydrogen is 2:3, we can calculate the number of moles of aluminum:

moles of aluminum = (2/3) * 0.32 moles ≈ 0.21 moles

Similarly, the number of moles of copper can be calculated by subtracting the moles of aluminum from the total moles of the mixture:

moles of copper = 0.32 moles - 0.21 moles ≈ 0.11 moles

To calculate the mass fraction of each metal, we need to divide the mass of each metal by the total mass of the mixture.

mass fraction of aluminum = (mass of aluminum / total mass of mixture) * 100 mass fraction of copper = (mass of copper / total mass of mixture) * 100

Substituting the given values:

mass fraction of aluminum = (0.21 moles * atomic mass of aluminum / 12 g) * 100 mass fraction of copper = (0.11 moles * atomic mass of copper / 12 g) * 100

The atomic mass of aluminum is approximately 26.98 g/mol, and the atomic mass of copper is approximately 63.55 g/mol.

Using these values, we can calculate the mass fractions of aluminum and copper in the mixture.