Question

Many computer chips are manufactured from silicon, which occurs in nature as SiO2. When SiO2 is heated to melting, it reacts with solid carbon to form liquid silicon and carbon monoxide gas. In an industrial preparation of silicon, 155.4 kg of SiO2 is allowed to react with 77.4 kg of carbon to produce 66.2 kg of silicon.a. What is the theoretical yield for the reaction in Kg Si?

b. What is the percent yield for the reaction?

Answer 1

theoretical yield: 72.50 kgSi

percent yield: 91.3%

Step-by-step explanation:

The theoretical yield is limited by the initial mass of the limiting reactant, SiO2. The mass of Si can be calculated using stoichiometry as follows:

155.1 kgSiO2 ×1 kmol SiO2/ 60.085 kg SiO2 ×1 kmol Si/ 1kmol SiO2 ×28.085kg Si 1kmolSi= 72.50kg Si

Percent yield is a comparison of the theoretical yield to the actual yield. The mass of Si actually produced is given as 66.2 kg . Dividing this by the theoretical yield (72.50 kg ) and multiplying by 100 % gives you the percent yield.

Answer 2

Theoretical yield for Si = 2586.55*28.09= 72.7 Kg

Percentage yield is =2356.71/2586.55=91.11%

Step-by-step explanation:

So the chemical equation for this reaction would be SiO2 + 2C = Si + CO

so n(SiO2)=m(SiO2)/M(SiO2)=155400/60.08=2586.55 mol

n(C)=m(C)/M(C)=77400/12.01=6444.63 mol

So Carbon is in exes.

n(Si)=m(Si)/M(Si)=66200/28.09= 2356.71 mol

Theoretical yield for Si = 2586.55*28.09= 72.7 Kg

Percentage yield is =2356.71/2586.55=91.11%