63

No. There are sweet, bitter, and various other salts. (Likely, there are tasteless salts too). Pure salty taste is as far as I know exclusive for table salt, though I wouldn't bet on it. Lead and Beryllium salts are said to be sweet, though toxic. Epsom salt, $\ce{MgSO4}$, is bitter. $\ce{CuSO4}$ has an incomprehensible, persistent metallic taste. (Based on ...


53

What would be the effect if someone were to drink ultra-pure, 18 M-ohm water? Not much, although if they drank many gallons of the water it could be a problem. Would they immediately die? No. Would they just need to pee more? Probably. Would $\ce{CO2}$ from the air (after the bottle is opened) and whatever's in saliva dissolve into the water ...


46

Menthol it self gives a cold feeling in the mouth because it is active at the same receptor (an ion channel) on the tongue that cold temperature triggers. Interestingly, although they act at the same receptor, they act at different sites, so that provides the intensified response when eating a mint and then drinking water. This reference gives an excellent ...


45

First of all, it depends on how the tap water was treated before it was piped to your house. In most cases, the water was chlorinated to remove microorganisms. By the time the water arrives at your house, there is very little (if any) chlorine left in the water. When you fill you container, there is likely to be some microorganisms present (either in the ...


41

One argument put forward has been that aluminum is very poorly bioavailable, moreso than many other elements. Aluminum oxide is very insoluble in water. In addition, any dissolved aluminum that does form in seawater is likely to be precipitated by silicic acid, forming hydroxyaluminosilicates. From Chris Exeter's 2009 article in Trends in Biochemical ...


37

I cannot think of anything in tap water that would make the water undrinkable after a couple of days already. Tagging the question with biochemistry probably points in the right direction. The only effect I can think about is growth of anaerobic microbes, e.g. Escherichia coli, causing diarrhea. There's good chance to keep the water from 'going bad' and ...


37

I will start my answer with a preface that the website linked to in the question is a pseudoscience website (and I am glad that it has vanished from the face of this earth, only accessible via the Wayback Machine). These people use scientific-sounding jargon that sounds impressive to the lay reader, but any actual scientist will know that it is simply ...


34

Saltiness is perceived when alkali metal enter taste buds. From wikipedia: Saltiness is a taste produced primarily by the presence of sodium ions. Other ions of the alkali metals group also taste salty, but the further from sodium the less salty the sensation is. The size of lithium and potassium ions most closely resemble those of sodium and ...


30

Methanol isn't particularly toxic in and of itself, although it's no walk in the park. If methanol flowed through the body without being broken down, it would cause roughly the same kind of harm as ethanol, i.e. intoxication. The real culprit is one of its metabolic products, methanoic acid, also known as formic acid. To understand how formic acid, ...


28

Sugar is made by repeatedly boiling and cooling cane syrup (or sugar beet syrup). After each cooling, the solution becomes supersaturated with respect to sucrose, causing sucrose to crystallize out of the "mother liquor" (the industrial term for the liquid solution from which crystals form). These crystals of "raw" sugar are heavily processed (washed in ...


27

Pure water (i.e. 18 Megohm conductivity) is still just water. If you don't drink so much as to cause water intoxication, it would be no different physiologically from drinking tap water or bottled water.


26

Cyanide is a pretty good ligand for coordination compounds. The electron pair on carbon (which, incidentally, also carries the Lewis structure’s formal charge) is located in the HOMO — much like as in $\ce{CO}$, whose molecular orbitals can be found in this answer by Martin (replace oxygen with nitrogen to arrive at $\ce{CN-}$) — making it a good Lewis base ...


25

These illustrations are by David Goodsell, and carry his famous look. Whilst I was not able to determine what specific software he uses, this page suggests that he probably creates his illustrations as a composite of renders and that the outlines and depth cueing are achieved by running a 'find edges' filter over the z-buffer of the scene, which can be ...


24

There is no fundamental law preventing simple chemical reactions: things are complex because of the combinatorial complexity of chemical compounds The complexity of many chemical reactions is a byproduct of the fact that there is a very, very large variety of possible chemicals. Much of that complexity happens because of the almost infinite way even some ...


23

It seems that NickT was looking for an experimental solution. My post deals, however, with a computational solution. How would I quantify how significant the interaction is? Determining the interaction energy between two defined monomers such as your aromatic triazole and amide is a rather straightforward process. This process is referred to as the ...


22

Excursion into simple coordination chemistry: Bonding, backbonding and simple orbital schemes Please refer to Breaking Bioinformatic’s answer for the MO scheme of carbon monoxide, it is very helpful. You might also look at the orbital pictures in this answer by Martin. Carbon monoxide can bind to metal centres via a σ coordinative bond where the HOMO ...


20

It doesn't make calcium carbonate rubbery, it removes the calcium carbonate. Egg shells are not purely calcium carbonate they are more like a composite with a continuous matrix of calcium carbonate and a smaller continuous matrix of protien. When you put the egg in vinegar, you etch away this calcium carbonate matrix leaving the formerly less noticeable ...


20

Yes it would, by a few percent. It may or may not be a goal worth pursuing, but there is more to it. Different reactions would be slowed down to a different extent. Tiny as they are, these discrepancies suffice to disrupt the delicate biochemical machinery of the living cell. No life form more advanced than bacteria is OK with that. Deuterated water in high ...


18

The enzyme alcohol dehydroganase converts the methanol to formaldehyde in the body. Formaldehyde is then converted to formic acid. Formaldehyde can cause blindness before being converted to formic acid, while formic acid causes acidosis as Williham Totland points out. See Biochemical Aspects of Methanol Poisoning for more information.


18

The presence of the hydrogen atom in the aldehyde group gives reducing properties to the aldehyde molecule. Aldehydes are easily oxidized by mild oxidizing agents such as Tollens’ reagent ($\ce{Ag+}$ in aqueous ammonia), Fehling’s reagent ($\ce{Cu^2+}$ complexed with tartrate), or Benedict’s reagent ($\ce{Cu^2+}$ complexed with citrate). Ketones do not have ...


17

The halogens, particularly in their diatomic free states and within various oxoacids, are strong oxidizing agents by virtue of their high electronegativities, electron affinities, and reduction potentials. The polarizability of the heavier halogens also makes them almost uniquely versatile as both good leaving groups and strong nucleophiles, depending on ...


17

It is essentially exactly what your teacher says: the term vitamin B complex is used because the structures assigned a name ‘vitamin Bx’ don’t really have anything in common although they are all somewhat important. As to why nobody ever uses vitamin K complex or vitamin D complex: well, at least in my country those vitamins are very under-represented when ...


16

permeakra is quite right with his counterexamples of salts that don't taste purely salty, but I'd like to expand on why. We haven't fully identified and elucidated the receptors involved in taste, but they can be broadly classed into tastes people are familiar with: salty, sweet, sour, bitter, and umami. Salty and sour receptors are both known to be mostly ...


16

As cibrail said, DNA is a polymer of nucleotides. They join themselves through phosphodiester bonds (a specific kind of covalent bond) that can grow to as much as millions of nucleotides. What part in the strand contributes to the overall non neutral charge? The reason why DNA is negatively charged is the phosphate group that makes up every nucleotide (...


16

The answer has to do with pi-backbonding. In essence, the CO molecule has a negative formal charge on the carbon (it's neutral because of the oxygen having a positive formal charge). However, C is quite electropositive, and would like to relieve the stress caused by the negative formal charge. To relieve the stress caused by the negative charge, the CO ...


15

Although I can't think of any drug examples other than thalidomide, here's information on thalidomide's mechanism: The chiral carbon of thalidomide can tautomerize in basic conditions into an enol, which is achiral. A reversal back to the ketone results in a mix of (R) and (S) enantiomers. In the body, this tautomerization is generally catalyzed by basic ...


15

According to the NIST ChemBook, 2-imidazolidinone and 2-imidazolidone are synonymous. The official IUPAC name is imidazolidin-2-one. 1,3-ethyleneurea is also another name for this same molecule:      But, as you note, tiny changes in spelling can sometimes be much more tricky than this. To take an example from this family: imidazolidinone and imidazolinone ...


15

The issue is one of yield. Each step has a certain yield percentage of yield, that the synthesizers will maximize as much as possible. However, given that it is fairly impossible to generate 100% yield all the time, the amount of desired protein you get over time will deteriorate exponentially with length. For example, say that each step gives you 95% yield....


15

Let me add to iad22agp's excellent answer. Often times in introductory biochemistry classes, the difference between phosphoanhydride and phosphate ester bonds is not adequately explained. ATP (and ADP) contain phosphoanhydride bonds. In these bonds, two phosphoric acid groups are condensed into one: $\ce{R~-H2PO3 + R'~-H2PO3 -> R-HO2P-O-PO2H-R' + ...


15

The $\ce{Fe}$-porphyrin complex is a vastly conjugated $\pi$-system, in which the oxidation state of the $\ce{Fe}$ plays a central role. The wavelength of light absorbed by hemoglobin exactly corresponds to the the difference in energy between the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the heme $\pi$-...


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