(R)-phenylalanine has a specific rotation of -70.0 degrees; (S)-phenylalanine has a specific rotation of +70.0 degrees. The optical activity of a sample of phenylalanine was measured, and a specific rotation of -56.0 was found.
a. Which enantiomer is in excess?
b. What is the enantiomeric excess (%ee)?
c. What is the percentage of (R)-phenylalanine present in this mixture?
d. What is the percentage of (S)-phenylalanine present in this mixture?