What is the Correct Calculation for Percentage Yield of Alkene from Alcohol?

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The discussion focuses on calculating the percentage yield of alkene from alcohol, specifically cyclohexanol to cyclohexene. The user calculates the number of moles of cyclohexanol using its density and molar mass, finding 0.136 moles. They confirm that the theoretical mass of cyclohexene, based on stoichiometry, is 11.17104 grams. Participants validate the calculations and clarify that while the number of moles remains the same, the molar masses differ. The user expresses gratitude for the assistance received in understanding the yield calculation process.
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We were preparing Alkene from Alcohol & were asked to calculate percentage yield.
We used 13.5 ml Cyclohexanol with 13.5 ml water & 7ml Sulfuric acid.

To calculate % yield,i need theoretical mass..
So i was calculating no.of moles of cyclohexanol & cyclohexene (the product) to get the theoretical mass.

No of moles of cylcohexanol = m/molar mass
mass = 13.5 ml x 0.926 g/ml (density) = 12.987 g
No.of moles of cyclohexanol = 12.987/100.16 = 0.136 moles

No.of moles of cyclohexne = no.of moles of cyclohexanol = 0.136 moles (from stoichiometry)
Theoretical mass of cyclohexene = n x M
=0.136 x 82.14 = 11.17104 g
Is this calculation correct?
 
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ChemDoodle said:
We were preparing Alkene from Alcohol & were asked to calculate percentage yield.
We used 13.5 ml Cyclohexanol with 13.5 ml water & 7ml Sulfuric acid.

To calculate % yield,i need theoretical mass..
So i was calculating no.of moles of cyclohexanol & cyclohexene (the product) to get the theoretical mass.

No of moles of cylcohexanol = m/molar mass
mass = 13.5 ml x 0.926 g/ml (density) = 12.987 g
No.of moles of cyclohexanol = 12.987/100.16 = 0.136 moles

Is this calculation correct?

Moreover, i need to calculate no.of moles of cyclohexene..What's the mass of cyclohexene i should take here? Should it be the same as cyclohexanol? Since according to the equation 1mole of cyclohexanol is supposed to yield 1 mole of cyclohexane.

Please help :)


The calculation looks correct. And as you said, next step is to find the number of moles cyclohexene. 1 mole cyclohexanol yield 1 mole cyclohexane, so there are the same numbers of molecules, but you should think about if two molecules have the same molar mass =)
 
saxen said:
The calculation looks correct. And as you said, next step is to find the number of moles cyclohexene. 1 mole cyclohexanol yield 1 mole cyclohexane, so there are the same numbers of molecules, but you should think about if two molecules have the same molar mass =)

I edited the first post with the continued calculations.Can u check that for me, please?
 
ChemDoodle said:
I edited the first post with the continued calculations.Can u check that for me, please?

It looks ok.
 
Thanku very much :D
 
ChemDoodle said:
Thanku very much :D

No problem, you know how to calculate the %yield?
 
saxen said:
No problem, you know how to calculate the %yield?

Yes :) Actual mass / Theoretical x 100
:D
Thanks for asking,really :) Most helplers here just make me feel inferior lol.
 
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