A 0.1 M solution enatiomerically pure chemical compound D has an observed rotation of 0.20 degrees in a 1 atm sample container. The Molecular mass of the compound is 150.
a. What is the specific rotation of D?(I already know this part )
b. What is the observed rotation if this solution is mixed with an equal volume of a solution that is 0.1 M in L, the enantiomer of D?
c What is the observed rotation if the solution of D is diluted with an equal volume of solvent?
d What is the specific rotation of D after the dilution described in c?

Question

A 0.1 M solution enatiomerically pure chemical compound D has an observed rotation of 0.20 degrees in a 1 atm sample container. The Molecular mass of the compound is 150. 
a. What is the specific rotation of D?(I already know this part )
b. What is the observed rotation if this solution is mixed with an equal volume of a solution that is 0.1 M in L, the enantiomer of D?
c What is the observed rotation if the solution of D is diluted with an equal volume of solvent?
d What is the specific rotation of D after the dilution described in c?

anonymous · Answer

I've already answered a. However, I don't understand b-d :(

anonymous · Answer

@Photon336  can you help me ? Thank you :)

photon336 · Answer

yeah enantiomerically pure means only one enantiomer predominates

photon336 · Answer

@Cuanchi have you taken organic yet? I forgot this formula

cuanchi · Answer

b. What is the observed rotation if this solution is mixed with an equal volume of a solution that is 0.1 M in L, the enantiomer of D? zero c What is the observed rotation if the solution of D is diluted with an equal volume of solvent? 1/2 of the original d What is the specific rotation of D after the dilution described in c? the specific rotation doesnt change with the dilution http://www.chem.ucla.edu/harding/tutorials/stereochem/calcs.html

photon336 · Answer

b racemic mixture, I think the rotation is zero. but if you notice if you add the same amount of the other enantiomer, they are not in a 1:1 ratio, you'll get zero for specific rotation. 

c. agree with cuanchi 

d.I'm pretty sure there won't be an affect here it will be the same.

anonymous · Answer

@Photon336 and @Cuanchi Thank you guys for helping me :) I'm sorry for responding so late.

anonymous · Answer

@Photon336  and @Cuanchi  I forgot to ask you what if e. What is the specific rotation of L, an enantiomer of D?

anonymous · Answer

f. What is the observed rotation of 1 L of solution that contains 0,01 mole of D and 0.005 mole of L?  (Assume 1 dm path length)

cuanchi · Answer

e. What is the specific rotation of L, an enantiomer of D?
the same than D but opposite sign.

f. What is the observed rotation of 1 L of solution that contains 0,01 mole of D and 0.005 mole of L?  (Assume 1 dm path length)

calculate the difference between the two enantiomers 
0.01 D- 0.05 L = 0.05 M "D"

specific rotation = observed rotation/ (cell path x concentration)

cells path = 1dm (doesn't affect anything in the formula we can ignore it)

observed rotation = specific rotation D x concentration D