**Introduction:**
- Enantiomers are stereoisomers that are non-superimposable mirror images of each other.
- Enantiomeric excess (ee) is a measure of the amount of one enantiomer present in a mixture of two enantiomers.
- It is expressed as a percentage and represents the excess of one enantiomer over the other.

**Specific Rotation:**
- Specific rotation is a measure of the optical activity of a compound.
- It is defined as the angle in degrees through which plane-polarized light is rotated when passing through a solution of a compound.
- The specific rotation is denoted by the symbol [α].

**Specific Rotation of Pure Cholesterol:**
- Pure cholesterol has a specific rotation of -32.
- The negative sign indicates that the compound rotates plane-polarized light counterclockwise (levorotatory).

**Specific Rotation of Sample of Cholesterol:**
- A sample of cholesterol prepared in the lab has a specific rotation of -8.
- The negative sign indicates that the sample also rotates plane-polarized light counterclockwise (levorotatory).

**Calculating Enantiomeric Excess (ee):**
- The enantiomeric excess (ee) can be calculated using the following formula:
ee = ([α]observed - [α]pure) / ([α]pure) * 100%
- [α]observed is the observed specific rotation of the sample (-8 in this case).
- [α]pure is the specific rotation of the pure enantiomer (-32 in this case).

**Calculating Enantiomeric Excess (ee) for the Sample of Cholesterol:**
- ee = (-8 - (-32)) / (-32) * 100%
- ee = 24 / 32 * 100%
- ee = 75%
- Therefore, the enantiomeric excess (ee) of the sample of cholesterol is 75%.

**Explanation:**
- Enantiomeric excess (ee) is a measure of the purity of a sample containing enantiomers.
- In this case, the sample of cholesterol has a specific rotation of -8, indicating the presence of both enantiomers.
- By comparing the observed specific rotation of the sample with the specific rotation of the pure enantiomer, we can calculate the enantiomeric excess.
- The positive value of the enantiomeric excess (ee = 75%) indicates that the sample contains an excess of one enantiomer over the other.
- A higher enantiomeric excess value indicates a higher purity of the sample, with a value of 100% representing a pure single enantiomer sample.