Using selected and high pure materials only, each density cube was lapped to 10x10x10mm to reach 1cm3 and 21.5×21.5×21.5mm (big 10cm3 cubes) in our lab with an accuracy of 0.01 millimeter. Each one separately ground and polished in a several hours lasting process. The cubes represent the theoretical density of the respective element by its weight.

Smart-elements.com

Luxury Periodic table display with LED illumination – NEW Design

Design & Made in Austria

Size: 1465 x 800 x 32mm.

118 double side LED illuminated compartments

Illumination: White daylight LED. Front material: brushed black Acrylic (other colors and materials available on request). Frame:brushed Aluminum.

https://www.youtube.com/watch?v=Bfd8DukeCLI
Youtube video showing using denatured alcohol (or methyl alcohol) and boric acid powder then lighting it on fire to make a coating to prevent oxidation during annealing. Not sure what metal he's doing it on.

I want to do it on the copper wire that has been stripped and is sticking out of an extension cord. Just wondering if this will work to soften the copper without interfering with the soldering that I'm planning to do afterwards (to repair the extension cord).

Thank you.

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Gaussian fit to overexposured spots

Saturation may occur when working with light emitting or absorbing systems. At first sight some of such systems might not seem to be saturated as seen on the densitogram of the upper image, ’sample full height [210 px]’. Though spots might look saturated the densitogram virtually does not confirms this. This is due to the large width of the lane.

A more realistic picture can be seen if we obtain a 3D projection/densitogram, (middle image), or narrow the width of the lane to be studied, (bottom image).

Narrowing the width of the lane to 30 px it results in some truncated Gaussian-like curves. Thus it is expected that an unsymmetrical Gaussian approach (BiGaussian) might serve with some better results.

Data are plotted: for full height in green, for truncated in red and for Gaussian fit in blue.

(Note: full height data were downscaled in order to fit into the graph).

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Hi I am a freshmen in college. I took a general chemistry class and I did horrible. My grade was lower than 60. I would spend hours and hours on homework but felt like I wasn’t memorizing anything and never did well on tests.

Hi, I'm looking for some fun chemistry demos that I can do outdoors for a chemistry club. It got to be relatively safe (no fire) and easy to set up, but also big enough to be a demo for outdoors. I already did a big elephants toothpaste (3 metres tall) demo with 50% peroxide and am looking for soming similar. Thanks

Basically, I'm looking to apply for a master's or straight PhD for chemistry, hopefully with a scholarship and I'm pretty much stumped on the first thing I need to do which is decide where to go. Europe is the destination in mind and yeah, I know how little that narrows it down. Asia too perhaps. That about narrows it down to 2/7th of the whole world. Progress. According to Google, places like Germany, Switzerland, Ireland, etc are the go to for Europe but I guess I don't really know about their chemistry programs and universities that offer them.

I'm typing this at 2am so I might not respond for a while. Also, I'm not exclusively like seeking out the best of the best schools. Just a low-key place I can be given a shot and do my best. Thanks!

im having so hard time in this subject right now and feel like crying. I am first year college MLS student and really not that good at quantitative chemistry so I am not quite confident whenever I am in this class. How do you manage to be good in analytical chemistry if you are not that good in solving equations?

I mixed some manganese carbonate and HCl to try to make manganous chloride. The HCl was pretty old and is hardware store quality, but has always been stored in the container it came in. The MnCO3 is from Sigma Aldritch and is decently pure. I added the carbonate until it didn't react vigorously- I want the solution to still have a little free acid in it.

When I've done this in the past, I've always gotten a pinkish MnCl2 solution, maybe with some wisps of black MnO2 in the bottom. This time I got a dark greenish-black solution. Did the old acid have something in it that oxidized the Mn instead of chlorinating it? What do I have a beaker full of, now? I've left it outside with the covering off in case I made MnO2, and that is now slowly making chlorine gas with the remaining HCl, but I really don't know what's going on in there. Any thoughts?

Title pretty much says it all. Trying to add abit extra to my essay but finding this bit hard. Any advice or places to look?

Been watching a lot of khan academy videos which are really helpful but wanting something interactive that gives me equations and so on so I have to grapple with the information more.

I’m imagining a duo lingo-type app but I’m not sure if it exists.

Also, any other resources that are good to learn from would help.

My level is about what 17-18 year olds study here in the UK. Maybe a bit below.

Is my thermometer in the right spot? The 99.9% IPA was previously used for cleaning glassware and a piperine extraction. I have 100mL of IPA distilled and I can still smell the piperine in it (faintly).

Can someone help explain what's happening?

I’m trying to decarboxylate glycine in sulfuric acid. Im afraid it might oxidize to HCN

I'm just curious about

Hello fellow chemists.

Is anyone here familiar with phospholipid synthesis?

I've synthetized a phospholipid derivative via esterification of a lecethin with the acyl chloride of a fatty acid and DMAP. I'm struggling with its purification. Column chromatography works well, but I would like to isolate the product via precipitation or crystalization. I tried beating, precipitation and crystalization with several solvents and mixtures of solvents, to no avail.

I couldn't find anything relevant in scientific literature (most of the articles I found talked about phospholipid extraction from biological material): apparently, the product is insoluble in ketones and ethers. I tried using these solvents, but I couldn't remove the impurities completely (one of them is residual fatty acid).

Do you know any valuable strategies, or some articles/textbooks with the information I need?

Thank you very much.

Looks like weed and melts at around 45-50 C. Smells flowery. Melted to a dark green color.

We have a Derakane (fibre glass) coated carbon steel tank that stores 33% hydrochloric acid. Somehow the protective coating allowed some hydrochloric acid to reach the steel and corroded a nice hole through the tank.

To do the repairs, we first need to make sure the space is safe to enter. We have ventilated the space for days but still we are getting high carbon monoxide levels (around 30-40 ppm).

We have had similar damage cases before, but carbon monoxide was never an issue.

Could the source of carbon monoxide be the reaction of HCl with steel?

In a copper electroplating bath, how can I have an anode that acts as a current source but at the same time does not "give off" copper ions? Is there any way I can make the ion source a different terminal while still having a controllable voltage across an inert terminal ? Thanks !

We have a chemical process where we mix lead and distilled water. On occasion, the solution is cloudy instead of clear. We have produced our own distilled water and have purchased water. We have the issue with both. Today we tested for all sorts of chemicals and we couldn't find any variances between tap and distilled. Please help! Thank you!

Hi! I am from Philippines and maybe, some of you here knows where I could buy 70% food grade ethanol for leaf extraction. Could you please drop the company or pharmaceutical name preferrably within the country? Thank you in advance.

Hi all,

We've in a situation in my lab where we are having a technician to come out to evaluate some issues with our glovebox (unexplained O2 spikes, cooling system control errors). During this visit & possible repair period, we will need to store our chemicals (mostly isocyanates and some solvents). The antechambers will also be tested, so we can't store in them. How would you go about this? In the past, we've stored a few things in another glovebox, but the location makes it a hassle to safely transfer materials. We have vacuum ovens in our lab; would storing them there under vac be suitable for a few day period? Thanks!

I have a bottle of giemsa stain solution (methylene blue, eosin, and azure b) and I would like to experiment with using it as a fountain pen ink. Is there any reaction that would take place between any of these chemicals and a stainless steel nib or plastic (couldn't find which specific plastic) ink feed that I should know about beforehand?

Hi! Not sure if this is the right sub. If not please let me know where else to post.

I am pregnant and have been getting very bad varicose veins despite being a healthy weight, fairly active, and eating well etc. I would just ignore them and figure it’s a purely cosmetic problem, but my mother almost died from blood clots while pregnant, so I am thinking maybe I should take this seriously while it’s still a small problem. It’s also uncomfortable enough to keep me awake some nights.

A friend took the supplement “Youthful Legs” for varicose veins and said it was very helpful. It has thousands of good reviews. The only real ingredient is micronized orange peel extract, containing diosmin and hesperidin.

This supplement is not available in my country and being pregnant I’d rather stay on the natural side anyway and find out if these compounds are either

A) available by blending up a whole orange with the peel and gagging it down

or

B) available in dry orange peel powder supplements, which would be slightly more palatable

I don’t know a lot about chemistry, but I do know that whenever dry herbal teas etc claim to be “an excellent source of Vitamin C” this is not true, because vitamin C is heat and light sensitive and is best consumed fresh. So dried rosehips have no Vitamin C, despite fresh rosehips having tons.

However since diosmin and hesperidin are flavonoids, would they not be destroyed by drying?

Every article I can find suggests drying or cooking the peel, but then the same article claims this is a source of vitamin C. I know that’s not true, so I wonder about the other claims it still has diosmin.

I can’t find any information on fresh orange peel for varicose veins, so I wonder if diosmin needs to be extracted to be useful.

Does anybody here have any information about this?

We were doing synthesis of some chromophore in organic nanoscience (1st year master student), I asked the lab technician for a fritte BC I don't like using paper filter when the product is solid

She gave me a brand new one I was so happy

The issue is that the end product is bright yellow and very insoluble, I tried DCM/methanol, ethanol, acetone, cyclohexane, ethyl acetate nothing is working

I need to find a way to clean it for next week, do you have any advice?

In a current project we are challenged by finding a solution on how to measure hydrogen sulfide (H2S) at trace gas levels in ambient air. Trace gas level means that we expect the concentrations to be in one-digit ppm range, or even below (upper ppb range).

Our recent research has led us to the following solutions:

• Electrochemical Sensors: Simple, very cheap, have a limited lifetime and are strongly affected by cross sensitivities such as mercaptans (that, for example, could occur in waste water channels)
• UV Fluorescence (UVF) Detectors: Do have very low detection limits, but only work with an internal converter that oxidizes H2S into SO2. Afterwards SO2 will be exposed into UV radiation and the SO2 fluorescence is measured. Disadvantage: Only SO2 is measured, so not providing knowledge about the real H2S concentrations if SO2 was already contained in the initial gas)
• GC-MS System: Could work well with a flame-photometric detector, but requires a fully passivated system (transfer lines, etc., to avoid absorption of the H2S on the tube walls); Furthermore: Application of GC-MS systems require an extractive sampling method while real-time analyzing is not possible.

Do you have any ideas about other capable devices that we did not find yet?