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21

Silver is not as inert as gold. Tarnish is the name we give to the phenomenon when silver metal is oxidized and becomes a salt. Surfaces made of silver tend to disinfect themselves pretty quickly. As for disinfecting water poured into a silver cup, I imagine that would take a little longer since you have to wait for silver to diffuse away from the surface ...


21

Circulated Coin I'll assume that the coin is circulated so a very gentle cleaning won't be a problem. You want to use some sort of organic solvent to loosen the glue, then very gently rub the residue off. You don't want to use any sort of silverware polish or anything abrasive when rubbing the coin. Good solvents might be olive oil or nail polish remover. ...


11

Well, $\ce{Ag2O}$ is just a basic oxide. As such, it would dissolve in suitable acids ($\ce{HNO3}$ would do), but I guess that's not quite what you want. Well, some metal oxides ($\ce{ZnO}$, for instance) are amphoteric and thus would dissolve in $\ce{KOH}$ as well, via formation of hydroxo complexes. Sadly, this is not the case with $\ce{Ag2O}$. Then we ...


11

As far as I know, a chunk of solid silver will not spontaneously react with water. But if you pass an electrical current through silver electrodes immersed in water, the silver will be oxidized according to the following equation: $$\ce{2H2O(l) + 2Ag(s) -> 2Ag+(aq) + H2(g) + OH- (aq)}\qquad E^\circ=-1.63\ \mathrm V$$ That will get you the ions you ...


11

You're right: the silver is reacting with sulfur compounds in the food to form a tarnish of silver sulfide. This is most commonly observed, in my experience, using silver teaspoons with boiled eggs, which are pretty rich in sulfur. There are a number of reactions that can take place depending on the sulfur-containing species - the abstract from this paper ...


9

Put them into a pot with some club soda and a piece of aluminium foil and pour over a hot water. I am familiar with this process. I am not familiar with the other. Perhaps someone else can provide an answer for it. What happens chemically during these procedure - why does it work, and what are the byproducts of these reactions? This process cleans ...


8

As to the above answers I also want to include the mechanism of action of silver as an antimicrobial agent. The exact mechanism of action of silver as an antimicrobial agent is not known and the current hypothesis is silver will converted to silver ions and this positively charged ions will attack the cell membrane, DNA or proteins which are negatively ...


7

A glance through the table of the isotopes in the venerable CRC handbook reveals that the longest lived radioactive isotope of Ag is $Ag^{108m}$, made by neutron capture by $Ag^{107}$. this has a listed half life of "> 5y", but the capture cross section is only $35\pm5$ barns, pretty small for thermal neutrons. So, it would be really hard to get a lot of ...


7

The solubilities of silver halides decreases down the periodic table: $\ce{AgF}\ : K_{sp} = 205$ $\ce{AgCl}: K_{sp} = 1.8\times10^{-10}$ $\ce{AgBr}: K_{sp} =5.2\times10^{-13}$ $\ce{AgI}\ \ \ : K_{sp} =8.3\times10^{-17}$ The rationale for this trend is typically described using the concept of hard/soft acids and bases. (See J. Chem. Educ., 1968, 45, ...


7

To give some numbers to MaxW's comment, you can see on this webpage the x-ray absorption energies of basically all the elements. For example, the K-edge of potassium is $3.61~\mathrm{keV}$. The L-II edge of silver is $3.52~\mathrm{keV}$ and the L-1 edge of silver is $3.81~\mathrm{keV}$. So, it seems like you are somehow automatically assigning the peaks and ...


6

Barium nitrate has a water solubility of $\pu{10.5g/100mL}$ at $\pu{25^oC}$. It isn't specified in the question what concentration of sulfate you suspect might be present, but given that you are trying to check for sulfate by precipitating with barium, barium nitrate should be the way to go.


6

Your choices are restrained as the precipitation of $\ce{SO4^{2-}}$ in $\ce{BaSO4}$ is the classical way to quantify the former and an electrochemical determination (in aqueous solution) is not practical. Electing $\ce{Ba(OH)2}$ may lead to the formation of silver hydroxyde, equally poorly soluble in water. $\ce{Ba(PO3)2}$ itself is very poorly soluble, as ...


6

To put the other answer in a graphical context, I took the X-ray emission spectra of K and Ag from some place online*, and plotted them together, crudely resized to fit the same scale. Some of the Ag L-lines (I think it's Lβ 1 and/or 2) are at exactly the same position as the K Kɑ line. So, the software sees a certain amount of counts at K, and identifies it....


5

Silver in silver oxide is no more oxidized than in $\ce{AgNO3}$. So you should ask yourself the same question earlier, even before the reaction. Yes, noble metals are somewhat resistant to oxidation. But still they can be oxidized, and thus can form compounds, of which $\ce{AgNO3}$ and $\ce{Ag2O}$ are the examples. Even gold can be oxidized, though that ...


5

The most important radioactive silver nuclide is Ag-110m (half-life: 249.9 d), which is generated in nuclear reactors. The effective dose coefficient of Ag-110m for ingestion by adult members of the public is 2.8E−09 Sv/Bq. However, this committed dose is evaluated over 50 years. In order to estimate the deterministic short-term effects of radiation ...


5

Silver's pretty soft—it's possible to just scrape it off with a metal spatula or something. Also, not all of the silver deposits on the glass. You might be able to adjust the conditions of the reaction to make more silver precipitate into the liquid where it's easier to get at. You can, of course, redissolve the silver in nitric acid or the like. Since the ...


4

Manishearth points to the right direction, the crucial parameters to look at are the standard electrode potentials. One should however take into account that the relevant species that get reduced under the condition of the Tollens' reagent are not the aquo- but the amine complexes, namely $\ce{[Ag(NH3)2]+}$. and $\ce{[Cu(NH3)4]^{2+}}$, respectively. ...


4

For the particular reaction where you get a silver mirror with an aldehyde, I doubt it'll work for copper, due to the reduction potentials. I'll take acetaldehyde $\ce{<->}$ acetate as an example here, but I believe that the reduction potentials of most aldehydes will be similar. The nitrate is a spectator ion here, so we need not consider its presence....


4

I suggest to do the following: Line the bottom of a pan with aluminum foil. Put the silver piece on top of the aluminum foil. The silver piece and aluminum foil must be in contact with each other. To about 2L of hot boiling water add about a half cup of baking soda (Be careful!). Then add the mixture to the pan. Make sure to cover the whole silver piece. ...


4

The concerned silver nuclide with 61 neutrons is $\ce{^108_47Ag}$. This nuclide with 47 protons and 61 neutrons lies in the so-called valley of β-stability. Image taken from Choppin, Liljenzin, Rydberg: Radiochemistry and Nuclear Chemistry, third edition (2002), p. 42 Nuclides on right side of the valley (higher neutron numbers) are unstable to decay by β− ...


4

You would get silver at the cathode, and oxygen at the anode. Since silver is below hydrogen in the spectrochemical series,it tends to get reduced over hydrogen, similarly, since $\ce{NO3-}$ is above $\ce{OH-}$ , it tends not to get oxidised, therefore giving oxygen. $\ce{Ag+ + e- -> Ag}$ (at cathode) $\ce{ 4OH- -> O2 + 2H2O + 4e-}$ (at anode)


4

AgO (silver(I, III) oxide) is unstable and decomposes to produce $\ce{O2}$ in aqueous solutions. Hydrogen peroxide is thermodynamically unstable too and slowly decomposes to form water and oxygen. Decomposition of hydrogen peroxide can be catalyzed by different compounds, including transition metals (such as Ag) and their compounds. Probably, the silver (I) ...


3

Hydroxide is bad for this process. You will have additional problems if hydroxide anion is present. Silver cation reacts with hydroxide anion to form silver hydroxide, which spontaneously decomposes into silver oxide: $$\begin{aligned}\ce{Ag+ + OH-}&\ce{ -> AgOH}\\ \ce{2AgOH}&\ce{ -> H2O +Ag2O}\end{aligned}$$ In addition to shutting down the ...


3

The energy in the electromagnetic radiation decomposes AgCl into its components, silver and chlorine. This produces finely divided silver particles, which look dark because yet solid silver (in the form of an ingot, for example) has a typical metallic 'colour', silver powder is dark.


3

If one needs to work with organic solvents, silver(I) oxide can be dissolved in trifluoroacetic acid (TFA) producing silver(I) trifluoroacetate $\ce{AgOCOCF3}$, which is a versatile reactant in organic synthesis (compact overview: [1]); also a precursor or chloride precipitant in the synthesis of metal complexes (see, e.g. [2]). References Wistrand, L.-G.; ...


3

If you had included the units in your calculation, you would have noticed why your equation is not correct. Molar mass $M$ is defined as $$M=\frac mn\tag1$$ where $m$ is mass and $n$ is amount of substance. Since the Avogadro constant $N_\mathrm A$ is $$N_\mathrm A=\frac Nn\tag2$$ where $N$ is the number of particles, the mass $m$ of one atom $(N=1)$ is $$m=...


3

Since the lab is past due now, I'll give what I think is the answer. $\ce{Ag2SO4}$ is somewhat soluble in water. It is most likely that you simply didn't get enough to cause precipitation. The other possibility, which I don't think applies here, is that you have a supersaturated solution. There are some precipitates for which crystals are just stubborn to ...


3

You can use hydrated tri-sodium citrate, it's readily soluble in water. As for its chemical reactivity, it's identical to tri-sodium citrate. You should take into consideration the increase in the molecular weight in the hydrated form due to the presence of water molecules.


3

Is any one of these reaction more "true" (occurring more often naturally) than the others or is it the case that a little bit of everything is happening? I think the best answer is "a little bit of everything". Silver sulfide forms faster but requires exposure of the silver to sulfur-containing materials (like human skin, food, etc.). Silver that isn't ...


3

The precipitation reaction is: $$\ce {Ag+ + Cl- -> AgCl_{(s)}}$$ The next reaction is: $$\ce {AgCl_{(s)} +Cl- -> AgCl2- }$$


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