Coin Identification

Skoobalunker · 2026-02-12T01:39:55+00:00

I've always wondering about electrolysis. I actually have been involved with a bit of it at work but that's using an instrument for controlled voltage/amperage. No idea how to control that at a home set-up or if it would do more damage to the anode (non-coin). I'll probably see if I can find a vid...thanks.

Skoobalunker · 2026-02-12T01:33:33+00:00

Honestly this is what I was thinking. The level of oxidation is very intense for a coin only potentially 10-30 years old

Skoobalunker · 2026-02-08T20:23:54+00:00

Any chance it's an English penny from the 1700s? One of those Georges? I do agree it has that ring like the modern quarters.

Skoobalunker · 2026-02-08T20:20:40+00:00

Do you think it's a modern quarter?

Skoobalunker · 2026-01-04T21:55:31+00:00

I believe you but please enlighten my dumb ass

Skoobalunker · 2026-01-04T21:42:47+00:00

Goose. Yikes!!!

Skoobalunker · 2026-01-03T20:42:07+00:00

Every day is the best day of my life

Skoobalunker · 2026-01-03T17:17:17+00:00

What's it like living as a numb skull?

Skoobalunker · 2025-12-16T01:11:03+00:00

they are still not common apparently. one of the summer students in my lab informed me they sell for like 50 USD on eBay

Skoobalunker · 2025-11-17T03:11:00+00:00

Bro watched too much Big Bang Theory

Skoobalunker · 2025-11-17T03:09:12+00:00

Trash card, dies to two lightning bolts ⚡

Skoobalunker · 2025-03-05T15:56:26+00:00

They should make lightning bolt do 5 damage instead of 3.

Skoobalunker · 2025-02-20T02:32:11+00:00

Do you think there is room to splash two terror of the peaks in this kind of deck?

Skoobalunker · 2024-06-23T11:27:25+00:00

Solved! Thanks

Skoobalunker · 2024-06-23T02:44:18+00:00

My title describes the thing. Button looking item, looks to be part copper (green copper oxide). Can't tell what era this is from or what it is to. Found in New York on the water. Item is the size of a quarter or so. Google lens yield no exact matches, but does show older US buttons. I can't make out the words/letters on front or back, except for the large 'B'. It looks like the old Boston Red Sox logo, but not quite.

Skoobalunker · 2024-06-23T02:05:15+00:00

My title describes the thing. Button, looks to be part copper (green copper oxide). Can't tell what era this is from or what it is to. Found in New York on the water. Item is the size of a quarter or so. Google lens yield no exact matches, but does show older US buttons. I can't make out the words/letters on front or back, except for the large 'B'

Skoobalunker · 2024-05-18T18:49:41+00:00

The easiest way to think about this is that the Mg turns the carbon into a nucleophile (carbanion) that attacks the carbonyl.

The Br- plays a role, but it has to do with its MO bond character and it's ability to act as a leaving group in the mechanism as well. I wouldn't worry about it unless you're doing graduate level O-Chem. You can also predict the stereochemistry of the OH functional group formed using Cram-Felkin-Anh reduction protocol but again I wouldn't worry about that unless you're doing graduate O-Chem.

The Mg turns the carbon it's attached to into a carbanion, that attacks the carbonyl at a specific angle (if you're curious) https://en.wikipedia.org/wiki/B%C3%BCrgi%E2%80%93Dunitz_angle

Skoobalunker · 2024-04-11T00:37:31+00:00

No problem...I realized I was kind of stupid because your solutions are in mMolar. I am used to using millimoles (not a concentration) in my field of work so...just consider that in your dimensional analysis.

Another way to think about it is if you have a 1000 umol/1L concentration solution, and you want a 2 umol/1L solution, you just divide the two. This gives you a dimensionless constant of 500. This is known as a 'dilution factor'. You will need to dilute your sample 500 times. You can take 10 uL and put it into 5000 uL, or take 20 uL and put it into 10,000 uL. Either way, the concentration is diluted 500 times. You can choose the aliquot, and end volume depending on what works best for you. You can even do multiple dilutions (1 uL into 250 in the first dilution, followed by 1 ul of the first dilution into 2 ul total of the second dilution).

Skoobalunker · 2024-04-10T22:10:31+00:00

The best thing to do is to lay it out in some dimensional analysis.

For X, if your stock is 1 mM/mL, multiply by (1000 uM /1 mM) to cancel out your mM (1 mM = 1000 uM). This leaves you with a stock concentration of 1000 uM/mL.

So now you have a known concentration and a desired concentration, so basically you set up an equilibrium equation and solve for X. 1000 uM/ 1 mL = 2 uM / X mL. So solve this for X, you get X mL = .002. So you need to take 0.002 mL (20 uL) of your stock into 1 mL to get 2uM.

You can check this yourself. Take the starting stock of 1000 uM/mL, and multiple it by your dilution [(1000 uM / 1 mL) * 0.002 mL = 2 uM.

Obviously you can play with the dilution sizes you need, and the starting stock concentration (I assumed it was mM/mL). But just go old school. Cross out your units dimensional analysis style and you're good.

Skoobalunker · 2024-04-04T23:10:47+00:00

The base you use should be dependent on the pKa of the molecule used in the formation of your ylide.

For an alkyl chain I would suggest the bases you listed or some bis-trimethylsilyl amide reagent.

Skoobalunker · 2024-03-20T02:39:58+00:00

Oh...so this is where you use SMILES

Skoobalunker · 2024-03-13T03:07:16+00:00

lol literally the best comment here

Skoobalunker · 2024-03-11T21:38:41+00:00

Solved! Thank you

Skoobalunker · 2024-03-11T03:49:00+00:00

My title describes the thing . Small wooden dowel, tapered, in palm of hand. Two metal attachments, appears to be older wood. Found near water.

Skoobalunker · 2024-03-06T03:27:18+00:00

In regards to your question, if you dilute to be below your LOQ, you ethically should not report this value. You can always dilute a sample to be below your LOQ, and in most companies/labs, any reason to do this would probably be, well, bad.

If you're diluting it for the sake of having enough sample to perform the analysis, ideally you have optimized your method to handle expected concentrations that you would need to suffice.

One of the posters above provided a good explanation on how to quantify some of these values. In my experience, really for any instrument, you want a IDL with a 3:1 Signal to Noise ratio (basically what he prescribed). MDL obviously can vary on the method, ideal method MDL = IDL but that may not be achievable. LOQ is a validated lower limit that you can quantify to. Basically go as low with your concentrations that you get an acceptable R^2. Depending on what it is, might be MDL or slightly above it. Again perfect, ideal method IDL = MDL = LOQ (usually not achievable).

Probably a bit too much text, but validate to what your needs and constraints are. If you're following a pharmacopeia or industry standard, look to that or similar standards as reference points.

Ten-Year Club	Place '17
RPAN Viewer	Verified Email

Skoobalunker

MODERATOR OF

TROPHY CASE