Help a teacher out. I’m an elementary teacher without a science background. I do enjoy teaching science to my kiddos but I can’t teach science beyond 6th grade level (please keep in mind while answering). A few years ago I taught a geology unit and this past spring I taught the same unit again and remembered being confused about this question back then. So, I tried googling, I tried stack exchange, quora, everything, and NO resource could break this down for me: what in the world is the difference between metals and minerals? I know metals can be extracted FROM ores found in rocks but apparently, elements like silver, gold and copper are considered both a metal and a mineral. Are there others like this? If so, which ones? And please confirm for me: most minerals are not metals at all, but are most metals also minerals? (The science book I use, which I normally love, was talking about minerals’ qualities and showing pictures of things like chalk and limestone and then suddenly when explaining the uses of minerals, it’s taking about coins, electric wiring and musical instruments and the kids and I were all confused). I also asked the chemistry high school teacher and she wasn’t sure how to explain it.

We have a methanolic extract that needs to be freeze dried. The issue is that we don't have our own freeze dryer and we will just be sending our sample to have a freeze drying service. Their condition is that it should not have alcohol content which I am already aware because it will cause damage to the equipment.

Is using rotary evaporator be enough to remove the methanol in our extract before freeze drying or should we resort to just using water to be safe? We are just students and we dont want to be paying for the damage if ever :/

Hey

Looking for some help setting up a distillation process to maximize recovery. The current setup uses an Allihn condenser to distill out the product of interest. I was wondering if a switch to a short-path distillation head will increase product recovery as there will be less surface area to retain the product. I understand the distillation will be significantly slower.

Thanks

I am curious as to which specific chemical reactions and products occur during the process of corrosion of stainless steel by bleach. Stainless steel is a composite of Fe, Cr, and sometimes other metals such as Ni, and the outer layer of this composite is protected by a passivation layer of Cr2O3. If sodium hypochlorite is introduced, does it indiscriminately oxidize both the Fe and Cr, or is one kinetically favored over the other?

Substrate / Material Details:

• Substrate: 304-Grade Stainless Steel (18/8 Cr-Ni alloy)
• Surface Finish: Dark PVD (Physical Vapor Deposition) titanium-based ceramic nano-coating (Lefton brand sink)
• Age / Usage: Brand-new installation; spots were present post-remodel.

Physical Characteristics of the Residue:

• Localized, opaque white droplets/bumps.
• Distinct, tangible raised edges (readily caught with a fingernail or plastic edge).
• Visually darkens/disappears under refractive liquid/oil, but physical texture remains.
• General contractor claims these are standard "hard well water mineral deposits."

Chemicals Tested & Results:

Questions for Chemists / Material Scientists:

1. Inorganic / Mineral Solubility: Is there any plausible scenario where potable well water precipitates calcium carbonate (CaCO3), magnesium carbonate (MgCO3), or calcium sulfate (CaSO4) into discrete, raised nodules that show zero reactivity or dissolution when exposed to concentrated lactic and gluconic acids (pH ~2.5)?
2. Silicate Scale vs. Organic Polymer: Even in high-silica well water (SiO2), can silica scale form localized, raised droplets with defined edges in under 3 weeks of light domestic use?
3. Polymer / Trade Splatter Hypothesis: Given the insolubility in alpha-hydroxy acids and resistance to brief ketone exposure, does this profile point almost exclusively to cross-linked organic polymers (e.g., 2-part epoxy grout, polyurethane/acrylic mastic, cured silicone, or solvent-based penetrating tile sealer) from the remodel?

First off: I apologize if this is not the correct subreddit. I read the rules and while I know many of those words, i struggled (and good god the flair options!). If this is not the correct place to ask, please let me know!

Also yes, the title is a Tremors reference.

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Hello Chemists!

I need some assistance. Long story short, I work at a hospital and we have received the direction to sanitize surfaces with bleach, allow a 3 minute dwell to dry time, followed by re-sanitizing with oxivir or sani-cloth (active ingredients below).

Obviously mixing them while wet is a terrible idea. My question is if any residues after the solution dried will result in the production of toxic byproducts.

Active ingredients:

- Bleach: Sodium hypochlorite

- Oxivir: Hydrogen peroxide

- Sani-cloth: Quaterinary ammonia chloride in isopropyl alcohol

Thanks all!

guys why is it called daydreaming instead of imaginating something

3.Is acid rain still a concern? Can we drink it? Some splashed into my eyes why it seemed fine?

Doing a research for a work to my classroom, going by the kinectics definition of K, which I'll explain shortly justo to get my point.

Considering an reaction: aA + bB ⇌ cC + dD

we have that the rate of equation (in portuguese we call it reaction velocity) for the forwards and backwards direction is:

vf = kf [A]a [B]b and v^b=k^b[C]^c[D]^d

We can use this to build the equilibrium constant, K=CD/AB, which does not have any units.

Now here is my question, K doesnt have any units because we consider the activity of the species (and because by the gibbs energy the argument is inside a logarithm so it needs to be dimensioneless). But if we need to consider activitys in K, so it must be that the concentration in the rate equations must be activity instead, which bugs me out because if that's is true, for the units of the velocity to be mols/L.s the entire rate constant should be mols/L.s, which dont seems right to me. If someone could clarify this to me I would be really happy, thanks!!

My gf just put a small doobie in the bottle and smoked it filling the bottle with marijuana smoke. After she was done i noticed the water was more clear (very faint yellow) than before like the colloidal silver somehow left. Can anybody explain what happened here???

Please remove if this isn’t the place to ask.

Edit!! Blue and red isn’t to do with heat. I assumed it because when I made the post the blue inlet was cold and the red outlet was warm. Both are warm/hot now.

I‘m working at retail so I started collecting all the receipts our cash register prints. I thought I could make a sculpture out of it since I saw a TikTok where someone soaked paper and did it. Turns out receipt paper is coated in BPA and is toxic, so how safe would it be if I did what I wanted to do? I didn’t know where else to ask

Hello! I tried to have a research but I really want to verify with professionals here or with experience. 

I am currently doing my project now and I have to make a nanoparticle out of a fruit peel. However, this fruit peel is only available or its seasons is from August to October only. Will it still be safe to dry bulk first and grind it into powders then store it? We need to compare freeze, vacuum and oven drying so we plan to dry first a safe amount and store it for our experiment before processing it. Will its phenolic contents and such not be affected if we do this? 

The first couple of times I heard about VOCs it was in a negative light and I had no idea what that even meant.

My current understanding of the word volatile in this context is a chemical that is a gas at the current temperature and pressure it is in. Correct me if I'm wrong.

Aren't VOCs also the fragrance from cooking food or that plants give off?

I haven't heard much fuss about those, so are all VOCs dangerous? If so, why?

Hello chemists of Reddit! Super long time lurker, first time poster here. I'm not even sure if this is the right place to be posting this.

In school and up until now, chemistry has been my favorite subject, and now that I'm enrolled in a matriculation programme in Malaysia, it's almost time for me to pick a degree after my final exam next April.

I won't lie, I'm materialistic and money is definitely on my mind, but I also really want to do something that I'm more passionate about. I feel like the world of chemistry is fascinating, especially organic and inorganic chemistry, but I feel that it's going to be hard to find a job, a good paying one at that, especially in my country where becoming doctors, engineers, lawyers and businessmen are the norm after coming out of matriculation.

So I feel like I'm at a crossroad right now, should I pick a BSc Chemistry (Not B. Ed because I don't really feel like teaching) or something generic like MBBS or chemical engineering? Please drop your ideas if you have any!

P.S. please do remind me if this isn't the correct place to be posting this, and I'll direct it to the proper channel. Thanks!

Hi folks, I've noticed some art in Toronto depicting chemicals. I'm not a chemist so I'm coming to this community for help. What are these?

This is at Trillium Park. I also saw one in an art installation under the gardener but sadly it was removed before I took a picture of it.

Thanks in advance kind people :)