Question

Из карбида кальция массой 15 грамм,содержащего 4% примесей,получили ацителен ,который был превращен по реакции Кучерова в ацельдегид.Определить массу серебра,которая выделяется при взаимодействии этого альдегида с избытком раствора серебра

Answer 1

Уравнения реакций:

(1) CaC2 + 2H2O = Ca(OH)2 + C2H2

(2) C2H2 + H2O = CH3CHO

(3) CH3CHO + 2[Ag(NH3)2]OH = CH3COOH + 2Ag + 4NH3 + H2O
Рассичтаем количество вещества чистого карбида кальция:

n(ч.в.) = 100%-w(прим)*m(в-ва)/100*M = 0,96*15/64 = 0,225моль

По уравнению реакции (1):
n(C2H2) = n(Ca(OH)2) = 0,225моль

По уравнению реакции (2):

n(CH3CHO0 = n(C2H2) = 0,225моль

По уравнению реакции (3):

n(Ag) = 2n(CH3CHO) = 0,45моль

Рассчитаем массу серебра:

m = n*M = 0,45моль*108г/моль = 48,6г

 

Answer 2

Calculation of the Mass of Silver Produced

To determine the mass of silver produced when the aldehyde reacts with an excess of silver solution, we need to consider the reaction stoichiometry and the amount of aldehyde produced from the given mass of calcium carbide.

1. Calculate the mass of acetylene produced from the given mass of calcium carbide: - The molar mass of calcium carbide (CaC2) is approximately 64.1 g/mol. - The given mass of calcium carbide is 15 grams. - To calculate the moles of calcium carbide, divide the mass by the molar mass: 15 g / 64.1 g/mol = 0.234 mol. - Since calcium carbide contains 4% impurities, the actual moles of pure calcium carbide are 4% less: 0.234 mol * (1 - 0.04) = 0.224 mol.

2. Determine the moles of acetylene produced: - According to the reaction stoichiometry, one mole of calcium carbide reacts to produce one mole of acetylene. - Therefore, the moles of acetylene produced are also 0.224 mol.

3. Calculate the moles of silver required to react with the acetaldehyde: - The reaction between acetaldehyde and silver forms silver acetylide, which has a 1:2 stoichiometric ratio. - This means that for every mole of acetaldehyde, two moles of silver are required. - Since the moles of acetaldehyde produced are equal to the moles of acetylene, the moles of silver required are twice the moles of acetylene: 0.224 mol * 2 = 0.448 mol.

4. Determine the mass of silver produced: - The molar mass of silver (Ag) is approximately 107.87 g/mol. - To calculate the mass of silver, multiply the moles of silver by the molar mass: 0.448 mol * 107.87 g/mol = 48.37 g.

Therefore, the mass of silver produced when the aldehyde reacts with an excess of silver solution is approximately 48.37 grams.