[suRe_Panda]

[macman104]

[suRe_Panda]

What is 186+186?

372 - 12 = 360 which is full circle... I'm not sure what this means though =S
or why you are doing 186 + 186 to begin with =S

Also, what about the last question?? Was i right with the 65%

[macman104]

Because, you doubled the concentration.  At a concentration of 0.05 you got 186, at a concentration of 0.1, you got 12, that is because 186 + 186 = 372 degrees, which is equivalent to 12 degrees.  You were measuring rotation.  So a rotation of 372 is going to be the same as reading a rotation of 12.

The last one seems to easy, I want to agree with you.  However, I don't know for sure, and there is probably something I'm missing which is why I didn't answer.

[Borek]

[macman104]

[alphahydroxy]

4. In this experiment, the maximum isolatable yield of any one enantiomer is 50%, because the
amine is racemic. If the amine had been already partly resolved to 65% optical purity, what
would be the maximum yield of optically pure amine in this experiment. Explain.

65%? If the maximum yield is 50% for an enantiomer in racemic mixture, then wouldn't 65% be the maximum for a 65% pure enantiomer???

It's not actually 65%, though it's easy to think that at first sight...

Think about what an optical purity (or enantiomeric excess) of 65% actually means - how do you calculate this number? It doesn't mean that there is 65% of one isomer and 35% of the other...

[suRe_Panda]

4. In this experiment, the maximum isolatable yield of any one enantiomer is 50%, because the
amine is racemic. If the amine had been already partly resolved to 65% optical purity, what
would be the maximum yield of optically pure amine in this experiment. Explain.

65%? If the maximum yield is 50% for an enantiomer in racemic mixture, then wouldn't 65% be the maximum for a 65% pure enantiomer???

It's not actually 65%, though it's easy to think that at first sight...

Think about what an optical purity (or enantiomeric excess) of 65% actually means - how do you calculate this number? It doesn't mean that there is 65% of one isomer and 35% of the other...

The way i see it is that there is 65% more of one enantiomer than the other... could it be... 82.5% maximum yield? then if its 82.5 to 17.5% distribution that means the one enatiomer is in excess by 65% more. So 82.5 - 17.5 = 65%. So then would 82.5% be the maximum yield?

[alphahydroxy]

Yup, think you have got it !