Question

Cмесь опилок алюминия и серебра, в которой w(Ag)=30%, обработали избытком соляной кислоты, при этом выделилось 5,22 л. газа (н.у.). Какова масса исходной смеси? ПРОШУ ПОМОГИТЕ, даю 20 баллов!!

Answer 1

Решение в файле снизу:

Answer 2

Calculation of the Mass of the Initial Mixture

To calculate the mass of the initial mixture, we need to use the given information about the reaction and the gas produced.

Given: - The mass fraction of silver in the mixture, w(Ag), is 30%. - 5.22 liters of gas (at standard temperature and pressure) were produced during the reaction.

To find the mass of the initial mixture, we can use the ideal gas law and the molar volume of a gas at standard temperature and pressure (STP), which is 22.4 liters/mol.

The balanced chemical equation for the reaction between aluminum and silver with excess hydrochloric acid can be represented as follows:

2Al + 3AgCl + 6HCl → 3Ag + 2AlCl3 + 3H2↑

From the equation, we can see that for every 3 moles of silver produced, 2 moles of aluminum react. Therefore, the molar ratio of silver to aluminum is 3:2.

Let's assume the initial mass of the mixture is M grams. Since the mass fraction of silver is 30%, the mass of silver in the mixture is 0.3M grams. Similarly, the mass of aluminum in the mixture is 0.7M grams.

Using the molar masses of silver (Ag) and aluminum (Al), which are 107.87 g/mol and 26.98 g/mol respectively, we can calculate the number of moles of silver and aluminum in the mixture:

Number of moles of silver (n(Ag)) = (0.3M g) / (107.87 g/mol) Number of moles of aluminum (n(Al)) = (0.7M g) / (26.98 g/mol)

Since the molar ratio of silver to aluminum is 3:2, we have:

(3/2) * n(Ag) = n(Al)

Substituting the values of n(Ag) and n(Al) from above, we can solve for M:

(3/2) * [(0.3M g) / (107.87 g/mol)] = (0.7M g) / (26.98 g/mol)

Simplifying the equation, we get:

(3/2) * (0.3 / 107.87) = 0.7 / 26.98

Solving for M, we find:

M ≈ 0.0071 kg

Therefore, the mass of the initial mixture is approximately 0.0071 kilograms.

Note: The calculation assumes that the reaction goes to completion and that there are no other reactants or products involved in the reaction.

Conclusion

The mass of the initial mixture is approximately 0.0071 kilograms.