# Percentage yield calculations

1. Dec 5, 2009

### ChemDoodle

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?

Last edited: Dec 5, 2009
2. Dec 5, 2009

### saxen

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 =)

3. Dec 5, 2009

### ChemDoodle

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

4. Dec 5, 2009

It looks ok.

5. Dec 5, 2009

### ChemDoodle

Thanku very much :D

6. Dec 5, 2009

### saxen

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

7. Dec 5, 2009

### ChemDoodle

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