Question

Exercise 4.52 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, 155.2 kg of SiO2 is allowed to react with 77.6 kg of carbon to produce 66.2 kg of silicon.

Part A Determine the limiting reactant for the reaction. SiO2(s) C(s) SubmitMy AnswersGive Up Correct Part B Determine the theoretical yield for the reaction. Express your answer using four significant figures. m = 72.40   kgSi   SubmitMy AnswersGive Up Incorrect; Try Again; 3 attempts remaining Part C Determine the percent yield for the reaction. % SubmitMy AnswersGive Up Provide FeedbackContinue

Answer 1

Part-A: Ans:  SiO2 (s)

The respective chemical equation is

SIO2(s) + 2 C(s) --> Si(s) + 2 CO and the given quantities are 155.2 kg of SiO2 and 77.6 kg of carbon ,

mass(sio2)(M)=155.2kg=155200g
molar mass of sio2(Mr)=28.1+16X2=60.1
no of moles of sio2(n)=M/Mr=2582.36 mol

mass(C)(M)=77.6 kg=77600g
molar mass of C(Mr)=12
no of moles of C(n)=M/Mr=6466.6 mol

Ratio of Sio2:C = 1:2

no of moles of C should be= 2Xno of moles of sio2
= 2 X 2582.36  mol
= 5164.7 mol

But no of moles of C=6466.6 moles
Thus carbon is in excess and SiO2 is limiting reactant.

Part:B
In product side, Practical mass(Si)(M)=66.2kg=66200g
molar mass of Si(Mr)=28.1

No. of moles of Si = 2355.8 moles

ratio of Sio2:Si = 1:1
therefore no of moles(n) of Si=no of moles of Sio2= 2582.36 mol

Theoretical mass of Si = Mr X n
= 28.1 X 2582.36
= 72564.3 g

Theoretical yield = 100%

Part-C:

The percent yield for the reaction

% yeild of Si = 66200/72564.3 X100
= 91.2%

% yeild of reaction =