# percentage yield a-level q

i am confused on the first mark - where did the numbers come from, what eqn is being used? sorry if it is simple,,

Original post by studybug531

Hi, for this question you need to use the equation: percentage yield = (actual yield)/(theoretical yield) x 100.
I prefer to use moles for these calculations (which is the alternative method the MS has shown).

1. calculate the mass of cyclohexanol: since d = m/v, mass = dv, so the mass = 10 x 0.096 = 9.6 grams.
2. calculate the moles of cyclohexanol: moles = mass/Mr, so the moles = 9.6/100 = 0.096. Since the reactants and products are in a 1:1 molar ratio, this is the theoretical yield of cyclohexane.
3. calculate the moles of cyclohexane: moles = 5.97/82 = 0.0728.
4. Percentage yield = 0.0728/0.096 x 100 = 75.83%.v

Hope this helps!
Original post by Biolover2020
Hi, for this question you need to use the equation: percentage yield = (actual yield)/(theoretical yield) x 100.
I prefer to use moles for these calculations (which is the alternative method the MS has shown).

1. calculate the mass of cyclohexanol: since d = m/v, mass = dv, so the mass = 10 x 0.096 = 9.6 grams.
2. calculate the moles of cyclohexanol: moles = mass/Mr, so the moles = 9.6/100 = 0.096. Since the reactants and products are in a 1:1 molar ratio, this is the theoretical yield of cyclohexane.
3. calculate the moles of cyclohexane: moles = 5.97/82 = 0.0728.
4. Percentage yield = 0.0728/0.096 x 100 = 75.83%.v

Hope this helps!

thank you!!