Imagine a sample that is enriched in the R enantiomer. If the % ee of the sample is 83%,
(a) what percent of the mixture is racemic?
(b) What is the ratio of R to S?

Using a 1.0-cm polarimeter cell and a solution prepared by dissolving 2.54 g of glucose in 1 L of H₂O, the specific rotation of d-glucose was calculated to be +52.7° at 20 °C using the sodium D line as the source of light. What was the observed rotation of the solution?

A student wanted to measure the specific rotation of the following propionate derivative (density = 1.12 g/ml).

A sample of the pure compound was placed in a 10.0-cm polarimeter tube, and using the sodium D line, the observed rotation at 20°C was determined to be +46.6° . What is the specific rotation of the propionate derivative?

(S)-Propranolol, a drug used for the treatment of anxiety, has a specific rotation of -25.5° . Attempting to prepare it in enantiopure form, a chemist produced a compound that gave a specific rotation of -18.3° . What is the ratio of (S)- to (R)-propranolol produced by the chemist?

(R)-Selegiline, a monoamine oxidase (MAO) inactivator, was approved by the FDA in 1989 for the treatment of Parkinson's disease. In pure form, it has a specific rotation, [α]²⁰_D = - 11.0°. What is the expected specific rotation of a mixture containing 64% S and 36% R?

Cholesterol (50 mg) was dissolved in 10 mL of chloroform and placed in a 1.0-cm polarimeter cell. This solution produced an observed rotation (using the sodium D line at 20°C ) of - 1.58° . What is the specific rotation of cholesterol?

For the molecules shown,

(i) count the number of stereocenters present and

(ii) draw all possible stereoisomers.

(iii) Identify the relationships between stereoisomers as enantiomers or diastereomers.

(a)