Information for Preparing Pre-lab and writing Lab Procedures

Dear Students,

It was a pleasure working with you all during our first lab session. Well done on completing Lab 1!

I've received a common question from many of you across all seven sections: "How do we prepare the pre-lab?" and "How to write the Lab procedures while performing experiments?"

In General Chemistry, you were trained to write objectives and procedures before attending the lab. However, Organic Chemistry lab has different expectations. These are outlined in the lab syllabus (available under Files), but I want to emphasize the key points and changes here:

Pre-Lab Requirements:

• Read the lab manual thoroughly before coming to lab.

• Complete the pre-lab assignment and submit it to your TA at the beginning of the lab.

• Enter the experimental objective and relevant SDS (Safety Data Sheet) information into your lab notebook. Your TA will check this before the lab starts.

• A reaction mechanism is required only for chemical synthesis experiments.

  
  

Optional but Helpful:

You may choose to write down the step-by-step procedures from the manual in your notebook before the lab. This is optional—but if it helps you feel more prepared, I encourage you to do it. However, reading the lab manual beforehand is absolutely required.

During the Lab:

As you perform the experiment:

• Record the experimental procedures in your lab notebook in past tense and passive voice (e.g., “The solution was heated...”).

• Your procedure notes are crucial for troubleshooting. If your results are unexpected, a well-documented procedure can help identify where things went off-track.

• Include any changes, accidents, spills, restarts, etc., in your procedure notes. Observations alone won’t give you the full picture.

🔬 Example: Melting Point Measurement

Instruction vs. Procedure

Lab Instructions (What you’re told to do):

1. Place 2–3 mg of benzoic acid on a clean, dry watch glass. If the compound is not a fine powder, pulverize it using a micro spatula.

2. Load a melting point capillary tube by pressing the open end of the tube into the powder. Pack the powder into the closed end of the tube by tapping the closed end against the bench top. Repeat the cycle of loading and packing until you can see 1–2 mm of benzoic acid through the tube.

3. Set the orientation temperature to 110 °C with a slow heating rate of 1–2 °C per minute.

4. Record the temperature at which liquid first appears and the temperature at which the entire sample becomes liquid.

Lab Procedure (What you write during or after doing the experiment):

1. Approximately 2–3 mg of benzoic acid was placed on a clean, dry watch glass.

2. A melting point capillary tube was loaded by pressing the open end into the powdered benzoic acid. The sample was packed into the closed end of the tube by tapping it gently against the benchtop. This process was repeated until approximately 1 mm of solid was collected in the bottom of the tube.

3. The melting point apparatus was set to an orientation temperature of 110 °C, and the slow heating rate was set to be 1.5 °C per minute.

4. The melting range of benzoic acid was observed to be 122.5–123.8 °C, with the first signs of melting at 122.5 °C and complete liquefaction at 123.8 °C.

Let me know if you have any further questions. I’m looking forward to seeing you all next week—well prepared and ready to dive deeper into organic chemistry!

Best regards,

Dr. Yang