Chemistry with S-man

26/08/2026

How to Prepare 0.1 M Hydrochloric Acid (HCl) Solution
Preparing a standard HCl solution requires accurate calculation, careful dilution, proper labeling, and appropriate laboratory safety practices.
🔬 Key points:
• For 1 L of 0.1 M HCl, approximately 8.3 mL of 37% concentrated HCl is required.
• Always add acid to water — never water to acid.
• Work in a suitable fume hood and use appropriate PPE.
• Allow the solution to cool before making up to the final volume.
• For analytical/titration work, the solution should be standardized for accurate results.
⚠️ Concentrated HCl is corrosive. Follow your laboratory SOP and appropriate safety procedures.

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Chemistry IQ test
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25/08/2026

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25/08/2026

Q32 | Volatile Organic — Accuracy Challenge
How would you prepare 100 mL of 1.0 M acetone in water accurately?
📌 Given:
• MW of acetone = 58.08 g/mol
• Density = 0.784 g/mL
• Boiling point ≈ 56°C
Calculation:
Required acetone = 0.100 mol
Mass required = 5.808 g
Equivalent volume = 7.41 mL
⚖️ The accuracy challenge: Acetone is highly volatile, so evaporation during pipetting or transfer can reduce the amount actually delivered.
For improved accuracy, weigh acetone by difference in a tightly closable container rather than relying solely on direct volume measurement.
Then transfer quantitatively and make the solution up to 100.0 mL.
🧠 Key lesson: For volatile liquids, controlling evaporation during handling can be just as important as the calculation itself.
⚠️ Acetone is highly flammable. Keep away from ignition sources and work with appropriate ventilation and PPE.
🧪 Chemistry Preparation — Prepare Smart. Work Safe.

25/08/2026

Test your chemistry

23/08/2026

🧪 Preparing 1 L of 1× Complete Medium from 10× Stocks

How do you correctly dilute 2 M glucose, 0.2 M glutamine, and 1 M HEPES stocks to prepare 1 L of 1× working medium?

📌 Since each component is supplied at 10× concentration, use 100 mL of each stock:

🔹 2 M Glucose → 100 mL
🔹 0.2 M Glutamine → 100 mL
🔹 1 M HEPES → 100 mL
💧 Water → 700 mL to give a final volume of 1 L

Final 1× concentrations:
✅ Glucose = 0.2 M
✅ Glutamine = 0.02 M (20 mM)
✅ HEPES = 0.1 M (100 mM)

⚠️ Important: L-glutamine is heat-labile and should generally not be autoclaved because prolonged heating causes degradation. Sterile filtration and aseptic addition are preferred for sensitive cell-culture preparations.

Save this calculation for your laboratory preparation practice! 🔬📚

22/08/2026

🧪 Chemical formulas you’ll want to remember!
A quick chart for faster chemistry revision. Save it for later! 📚⚡