Question

Технический карбид кальция массой 20 г обработали избытком воды, получив ацетилен, при пропускании которого через избыток бромной воды образовался 1,1,2,2 –тетрабромэтан массой 86,5 г. Определите массовую долю СаС2 в техническом карбиде.

Answer 1

CaC2+H2O = Ca(OH)2+C2H2

C2H2+Br2 = CHBr2-CHBr2

n  CHBr2-CHBr2=86.5/346=0.25 моль

n C2H2=0.25 моль

n СaС2(теоретически)= 20/64=0.3125 моль

n C2H2(теоретически)=0.3125 моль

Из условий задачи видно что из карбида кальция получилось 0.25 моль ацетилена

m CaC2 =0.25*64=16 г чистого карбида

ω=m/M

ω=16/20=0.8*100%=80%

 

 

 

 

 

 

 

 

 

 

 

 

 

Answer 2

Calculation of the Mass Fraction of CaC2 in Technical Calcium Carbide

To determine the mass fraction of CaC2 (calcium carbide) in the technical calcium carbide sample, we need to use the given information about the reaction and the masses of the reactants and products.

The reaction can be represented as follows:

CaC2 + 2H2O -> C2H2 + Ca(OH)2

From the reaction equation, we can see that 1 mole of CaC2 reacts with 2 moles of H2O to produce 1 mole of C2H2 and 1 mole of Ca(OH)2.

Let's calculate the number of moles of C2H2 produced:

Given: Mass of 1,1,2,2-tetrabromoethane (C2H2Br4) = 86.5 g

To find the moles of C2H2, we need to convert the mass of C2H2Br4 to moles using its molar mass.

The molar mass of C2H2Br4 can be calculated as follows: C: 2 * 12.01 g/mol = 24.02 g/mol H: 2 * 1.01 g/mol = 2.02 g/mol Br: 4 * 79.90 g/mol = 319.60 g/mol

Total molar mass of C2H2Br4 = 24.02 + 2.02 + 319.60 = 345.64 g/mol

Now, we can calculate the moles of C2H2: Moles of C2H2 = Mass of C2H2Br4 / Molar mass of C2H2Br4 Moles of C2H2 = 86.5 g / 345.64 g/mol

Let's calculate the moles of CaC2:

Given: Mass of CaC2 = 20 g

To find the moles of CaC2, we need to convert the mass of CaC2 to moles using its molar mass.

The molar mass of CaC2 can be calculated as follows: Ca: 1 * 40.08 g/mol = 40.08 g/mol C: 2 * 12.01 g/mol = 24.02 g/mol

Total molar mass of CaC2 = 40.08 + 24.02 = 64.10 g/mol

Now, we can calculate the moles of CaC2: Moles of CaC2 = Mass of CaC2 / Molar mass of CaC2 Moles of CaC2 = 20 g / 64.10 g/mol

Finally, we can calculate the mass fraction of CaC2 in the technical calcium carbide sample:

Mass fraction of CaC2 = (Moles of CaC2 / (Moles of CaC2 + Moles of C2H2)) * 100

Let's plug in the values and calculate the mass fraction of CaC2.