Stereochemical Identification & Analysis Virtual Lab
Before beginning the experiment, complete this quiz to ensure you understand the key concepts. You must score at least 70% to proceed to the lab.
Before handling any chemicals, complete this comprehensive safety briefing and don all required Personal Protective Equipment (PPE).
Today's experiment involves handling organic acids. While these compounds are relatively safe, proper precautions are essential:
Click each item to learn about it and put it on.
Verify each item before proceeding:
You must acknowledge the key hazards before proceeding.
Measure the optical rotation of your unknown sample. Follow the detailed procedure below, completing each step carefully.
Drag vial to equipment
Determine the melting point of your unknown sample using the Mel-Temp apparatus. Pack a capillary tube and carefully observe the melting process.
Drag to Mel-Temp
Specific Rotation:
---
Tip: The melting point helps distinguish between compounds with identical optical properties. Meso compounds (~140°C) and racemic mixtures (~206°C) both show zero rotation but have very different melting points.
You must wear proper PPE (goggles, gloves, and lab coat) before handling chemicals!
Press TARE to zero the balance
Prepare a solution for polarimetry analysis
Sample Mass: --- g
Concentration: ---
Step 1: Zero the polarimeter with blank (water) first.
Observed Rotation (α): ---
Specific Rotation [α]: ---
Step 1: Pack the capillary tube with sample.
Melt Start: ---°C
Melt End: ---°C
Melting Range: ---
Please wait...
0:00
Review your experimental data, compare with reference values, and identify your unknown compound. Use both polarimetry and melting point data together to make your determination.
| Compound | Specific Rotation [α] | Melting Point (°C) | Classification |
|---|---|---|---|
| (+)-Tartaric Acid | +12.0° | 170 | Chiral (R,R) |
| (−)-Tartaric Acid | −12.0° | 170 | Chiral (S,S) |
| meso-Tartaric Acid | 0.0° | 140 | Meso (R,S) |
| (±)-Tartaric Acid | 0.0° | 206 | Racemic |
Click a row to compare with your experimental data
* = Chiral center
How did your polarimetry and melting point data lead to your identification? What key observations support your conclusion?
Calculate your percent error for each measurement:
Complete these reflection questions to demonstrate your understanding of the experiment and the underlying concepts. All questions must be answered to complete the lab.