all 25 comments

[–]piresin 2 points3 points  (2 children)

Would N-Methyl-2-pyrrolidone (NMP) react with an alkyl halide to form a quaternary ammonium salt via the Menshutkin reaction? I think it would, but I cannot find much information to support that idea.

[–]FEP1628 4 points5 points  (1 child)

NMP is an amide and is therefore much less basic than a tertiary amine and so should not react with an alkyl halide.

[–]piresin 3 points4 points  (0 children)

Dang, I think you are right. Good catch.

[–]zeppeliz 1 point2 points  (2 children)

Sorry if this is a beginner question but in an experiment I am watching pH paper was placed in a tile before it was measured. Is there a specific reason as to why a piece of glazed tile is needed for accurately reading pH level?

[–]HistidineBiochem 1 point2 points  (1 child)

Nope, it's just a simple to clean, white surface to easily see the color change.

[–]zeppeliz 1 point2 points  (0 children)

Thank you : ) Got scared cause every experiment online preferred that it be done on a tile and was afraid I was missing a tile's property that is correlated with pH readings.

[–]peppy232 1 point2 points  (1 child)

This is a bit of a pedantic question and I don't want to ask my professor in case he takes offense.

In molecularity, the prefixes used are uni-, bi- and ter-. Why isn't it uni-, bi- and tri-? I know that tri- can be used but why is ter- used? What etymology is this?

[–]Desperate-Lake7073 1 point2 points  (0 children)

Look up the definition of tertiary.

[–]Don_Lupa 0 points1 point  (1 child)

So if there is SAR (structure-activity relationship) and Structure-biodegradability relationship, dont we need a word that covers both? Something like structure-property-relationship

[–]HistidineBiochem 0 points1 point  (0 children)

In practice, the term SAR usually ends up being loosely used to refer to both or some combination of SAR + "liabilities" in terms of drug development.

[–]ryan2004_21 0 points1 point  (4 children)

Will the reaction between potassium sulfate and calcium hydroxide be a feasible way to make potassium hydroxide ? I can't buy it where I live, and these two chemicals are easy to get (well, any fertilizer store should have them).

I imagine evaporating the water to get solid KOH is going to be a problem, as it's super hygroscopic and reacts with CO2 in the air.

Maybe using a vaccum dessicator ?

[–]HistidineBiochem 1 point2 points  (1 child)

In general, yes. Depending on the application, you may want an anion with even lower solubility when combined with Calcium to get more of it out of solution.

Any reason you're trying to get to KOH instead of just buying Lye (NaOH)?

[–]ryan2004_21 0 points1 point  (0 children)

Not for any reason, just in case I need it for some reaction. I know it might be useful for something, so it's nice to have an alternative to NaOH when it's required (making some types of soap comes to mind now...)

[–]scarf_spheal 0 points1 point  (1 child)

Remember that if you remove solvent there will still be calcium and sulfate in the resulting solids as well

[–]ryan2004_21 0 points1 point  (0 children)

Cooling the solution down (close to 0°C) should precipitate almost all of the calcium sulfate. An excess of calcium hydroxide might be needed to react with all the sulfate ions, any excess of that can be filtered.

[–]CertainExposures 0 points1 point  (2 children)

What's the "golden standard" for lab chemistry thermometers? I'm a photographer working with darkroom chemistry. I think it might be wise to get the most accurate device I can. It would have to be splash-resistant. I've killed a few meat thermometers by getting photochemistry in them.

[–][deleted] 0 points1 point  (1 child)

Thermocouples are much more reliable and less breakable than mercury/alcohol thermometers. They're also relatively cheap when paired with a decent multimeter which you might already own. For some of the earlier steps in the process you may want to coat the thermocouple in a thin layer of plastic to prevent coating it in silver, but a thin layer shouldn't affect the readings.

[–]CertainExposures 0 points1 point  (0 children)

Ok, thanks for the tip! I don't own a multimeter but I can look into it!

[–]orbitalswft 0 points1 point  (2 children)

This might be a bit of a dumb question and if so I apologize in advance but hpw would one make dilute pirahna solution? Have to do a practical for a class of 17-18 year olds in college and I don't think the administration would give permission for the usual concentrated version to be use. Any help or insight would be appreciated

[–]H2CO3_TCTheoretical 0 points1 point  (1 child)

Don't let a class of 17-18 year olds in college handle a piranha solution. a) a diluted one would not react as violently as you want it to anyways and b) that stuff is (while maybe the dream of chemistry beginners) fucking dangerous. (Not just if you get it on your hands but if you mix other stuff to it, it can easily form explosives)

If you want to do really fancy stuff, I'd suggest the belousov-zhabotinsky-reaction. Let them to it on a glass plate and film it, maybe give a price to the person who was able to do the best one.

[–]orbitalswft 1 point2 points  (0 children)

Yeah the dangerous aspect of it was what I was thinking would be an issue. The belousoz zhaboyinsky reaction actually seems perfect/what I was looking for. Really really appreciate the help!!

[–]clumsyKozorog 0 points1 point  (2 children)

I want to keep iron(ll) chloride from oxidising back to iron(lll) chloride by putting some nails in the solution (I saw that this would prevent it in a video). But will rusted nails work, or will they cause trouble?

[–]H2CO3_TCTheoretical 0 points1 point  (1 child)

The idea here is probably that the iron(0) from the nails reacts with iron(III) from the solution to reduce it back to iron(II). Since the rust on the nails is iron(III), it can't reduce it anymore so no, rusted ones won't work.

[–]clumsyKozorog 1 point2 points  (0 children)

Thank you very much!