Wikipedia:Reference desk/Archives/Miscellaneous/2015 October 13

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October 13

White and bluer crystals in my water

http://imgur.com/a/UXzGH

While trying to solve other problems in my tap, I unscrewed the tip and this was in the mesh filter. Does anyone know what it is? If it was all white I'd assume it was calcium carbonate, but I'm a bit stumped on the blue. And can anything be done to prevent it? This buildup happened over the course of about a week. Seems like an awful lot. — Preceding unsigned comment added by 82.4.218.94 (talk) 15:43, 13 October 2015 (UTC)

See Copper(II) sulfate and an explanation here.--TMCk (talk) 16:16, 13 October 2015 (UTC)

Thanks. Now we just need to figure out who to talk to about this.

The blue suggests you have some copper plumbing. Yet that is not the end to the problem. This should not occur. If you have a very old copper plumbing system with a copper immersion cylinder, it might just be sludge on the bottom allowing stagnate water to devolve the copper. Or you may have a badly installed water softener or an electrical leakage (from say an immersion heater)to leach copper into the system. Check you eyes in a mirror for Copper toxicity. You are doing the right thing in not ignoring this blue peril. Also, if you have friend that is an qualified electrician, have him use a suitable meter to check that the plumbing system is not picking up stray currents. If that fails check with your local environmental health department at your town hall.--Aspro (talk) 16:23, 13 October 2015 (UTC)

I don't know how old the system itself is, but we just started noticing this when we had a new kitchen installed. No idea if it happened before. 82.4.218.94 (talk) 17:56, 13 October 2015 (UTC)

Unfortunately, I can't be in your kitchen to diagnoses the problem directly (unfortunate indeed, especially if your wife is a cook cook, as I accept payment in food as well as cash). So all I can do is point you to this blog of others that have had copper problems. [1]. Being a new kitchen, it might just be the flux on the soldered joints washing out. In which case, the incidence will fade over time. This question might be better suited to being transferred to WP Science Help Desk if the problem continues.--Aspro (talk) 19:40, 13 October 2015 (UTC)

Looks like verdigris (copper carbonate) to me. As you've recently had work done it's probably caused by the flux used when soldering. Remove the filter and run the tap for a few minutes and that ought to be an end to it.--Ykraps (talk) 07:29, 14 October 2015 (UTC)

Having just read the article verdigris, I think the scientific name is copper II acetate. In any event it is most likely caused by the acid in self-cleaning flux and once it's flushed through you shouldn't have any more problems.--Ykraps (talk) 09:46, 14 October 2015 (UTC)

I'm not sure it's possible to nail down exactly which "copper II" compound it is. Generally, all copper II compounds are bluish-green to greenish-blue, with the exact color determined by the exact formulation of the ion complex around the copper II atom, it could be a mish-mish of copper II compounds, including acetates, carbonates, sulfates, hydroxides, etc. The color is indicative of a copper II compound, but not indicative of which copper II compound. --Jayron32 15:34, 14 October 2015 (UTC)

Also, you'll note the verdigris article confirms the green coloration is not a specific copper II compound, but a mishmash of them; artificial verdigris (intentionally created by, say, an artist working in copper alloys) is most commonly acetate, because the acetic acid or vinegar is commonly used to accelerate the patina process. Natural verdigris is more commonly a combination of copper II carbonate and/or copper II chloride, depending on the local chemistry where the metal is corroding. --Jayron32 15:38, 14 October 2015 (UTC)

I don't think this is natural verdigris, I am almost certain it has been caused by the acid in flux. I thought it might be copper II acetate as this type of verdigris is formed through contact with acid, however I see now that the word acetate relates to acetic and the acids used in self-cleaning fluxes are much stronger than that. I am not a chemist but I am a qualified plumber with more than thirty years experience and I am sure that the original poster's problem is merely the result of some recent soldering and that running the tap for a while will solve it.--Ykraps (talk) 19:10, 14 October 2015 (UTC)

If you know the name of the acid in the flux, you'll know the copper compound in question, the anion of the acid will be the same as the anion in the copper compound.--Jayron32 21:55, 14 October 2015 (UTC)

I had hitherto thought it was hydrochloric but having checked the label, the only caustic ingredients are the chlorides, ammonium and zinc. I suppose the verdigris in that instance would be copper chloride then?--Ykraps (talk) 06:24, 16 October 2015 (UTC)

why does the pie bond alone exist in C2

Shahjad ansari (talk) 17:19, 13 October 2015 (UTC)

Assuming you mean pi bonds in Diatomic carbon, there are many models of C₂. Some, using either hybridization theory or molecular orbital theory predicts a double bond. Whether such double bonds are sigma + pi or two pi bonds really depends on how you define those terms. Molecular Orbital Theory predicts two pi bonds, see this molecular orbital diagram. Hybridization theory (and valence bond theory), would predict a sigma and a pi bond; as diatomic carbon would be a tetra-radical (chemistry) with a double bond between the carbons; each carbon would have sp² hybridization. Thus, there would be orbital overlap between the sp² orbitals and between unhybridized p orbitals. sp²-sp² overlap is a sigma-type bond, while p-p overlap is a pi bond. So, really when asking about the bonding in C₂, you need to specify "according to which theory..." Experimental evidence indicates that it's quite likely a double bond; bond dissociation energy data indicates it's quite likely a double bond experimentally, (though some more recent experiments indicate that it may be a rare quadruple bond, but those results are in dispute). So, there's your answer: according to VBT, it should be a sigma and a pi, and according to MOT, it should be two pi bonds. --Jayron32 17:36, 13 October 2015 (UTC)

You had the title and signature in the wrong place. I swapped them. StuRat (talk) 17:39, 13 October 2015 (UTC)

And there is also a related question on the science reference desk. Graeme Bartlett (talk) 12:52, 14 October 2015 (UTC)