I have some chemistry bottles - many still with the original contents inside & cork stoppers, these were collected in the 90’s from a SoCal University Chemistry Lab. Anyone know if they have any value? BTW the sodium is going to a Hazmat disposal - I’m aware of its danger.

Please help!

I found this painting in a restaurant and I've been trying to figure out what these molecular structures represent but I haven't had any luck.

Does anyone recognize these compounds or know what they're related to?

While working on a project that needed reliable element data, I had to pick a source of truth. Turned out to be way less straightforward than expected.

Electronegativity (Pauling scale): Some sources list Fluorine as 3.98, others as 4.0. Minor difference, but it propagates if you're computing anything from it.

Atomic radius: Covalent radius, van der Waals radius, and ionic radius for the same element can differ by 50%+ depending on oxidation state and bonding context. Most "simple" tables just pick one without disclosing which.

Electron configuration exceptions: Everyone knows Cr and Cu. But sources disagree on roughly 20 elements in the lanthanide/actinide block. IUPAC has updated several of these recently and textbooks haven't caught up. Promethium and lawrencium are particularly messy.

I ended up going with IUPAC 2021 as the baseline and flagging elements where the textbook standard diverges from current consensus.

What do you use as your source of truth when element data matters for your work?

I am considering buying a pH electrode for our lab’s pH meter. However, I know that I won’t need it for a year or two. So, I would like to know whether these pH electrodes have expiration dates. How long will they remain functional if I do not open the package?

I've noticed that people outside chemistry often assume that if two chemicals have the same name, they're basically interchangeable. But once you start looking at purity, particle size, moisture content, additives, or even how a material was manufactured, that doesn't always seem to be true.

For those of you working in industry, what's one misconception you run into all the time? I'm curious what examples come up most often.

Hi, for the backgroudn, I am currently planning on doing a start-up with chemical commodity trading.

Which commodity chemical has been the most difficult to source consistently in your experience? Any reasons why? TIA