# Tag Info

27

How long will these reserves last? Short answer: longer than you think and will outlast me, you, our children and our grandchildren. Possibly last forever. Long answer: This is a fairly complex issue. There was a book published about this topic several years ago claiming that we are running out of metals. Turns out that the book had a major flaw in its ...

19

The analytical technique is called inductively coupled plasma optical emission spectroscopy. It was invented by a chemist V. A. Fassel, although it is pure physics. The specimen is digested in an acid, and a fine spray is created. That "spray" is heated to a temperature, which is higher than the surface of the Sun. Most of the elements of the periodic table ...

13

Obsidian This is a volcanic glass, formed when rhyolitic lavas cool too quickly for crystals to form. From a chemistry point of view, it's a mixture of silicon dioxide, aluminium oxide, with sodium ,potassium, calcium and iron oxides in various quantities. These lavas will also contain significant volatiles (water and $\ce{CO2}$) held in solution by ...

12

Inductively Coupled Plasma (ICP) based techniques are very common for elemental analysis. The goal of such analyses is to quantify the elements present in a sample. The neat thing about this, in my opinion, is that the integrity of the molecular compounds does not need to be maintained throughout the analysis, since we only care about the elements that ...

9

You could proceed from either end member of the olivine solid series and yield $\ce{SiO2}$ as you suggest. However, I'd consider mechanisms that have been researched in the course of studying so-called mineral sequestration in addition to what you've written, especially considering the energy requirements you propose: the mineral sequestration reactions are ...

8

1) Oxygen CAN form 3 or 4 bonds. The most common example is $\ce{H3O+}$ ion This form of bonding is critical to understand basic nature of ammonia solutions, so for exact description of it look that part of the book. 2)Boron also can form more than 3 bonds if at least one its partner provides an electron pair for bonding, not one electron. As a general ...

8

Some radioactive materials are made by man, others have been parts of earth's rocks since they were formed Radioactive materials are not all the same. some are man-made and some have been with us since the creation of the planet (so are indeed the product of old exploded stars). The best way to tell which is which is to look at the half-life of the atoms ...

7

A number of papers report that the formal valency states of chalcopyrite are best considered as $\ce{Cu+Fe^3+S2}$, based on various computational and spectroscopic evidence. References: Klekovkina, V. V.; Gainov, R. R.; Vagizov, F. G.; Dooglav, A. V.; Golovanevskiy, V. A.; Pen’kov, I. N. Oxidation and magnetic states of chalcopyrite CuFeS2: A first ...

7

Neutron activation analysis is a technique that can be used for trace mineral quantification in a sample. You start by irradiating your sample in a small experimental nuclear reactor. These were more common in the 1960's and '70's than they are today. Slow neutrons are absorbed by many different isotopes, converting them to radioactive species. The sample ...

6

$\ce{Al2O3.nH2O}$ is just a general (and slightly incorrect, see below) way of writing the formulae of the aluminium oxy-hydroxides that occur in bauxites. These are solid minerals, so there is no "$\ce{Al2O3}$" molecule in them. Instead, it is an (almost) infinite array of Al and O ions in a three dimensional structure. Therefore, what it basically means is ...

5

The previous answer is not really helpful because you would need huge amounts of CO2 which are not available on the moon. You need 2 moles of CO2 to generate 1 moles of SiO2. You simply do not have that amounts of CO2. Furthermore, assuming you do someone get that CO2, you need to physically separate the Mg and Fe carbonates from the silica. One way would ...

5

I don't think acid rain formation from liquid acid mine drainage is very likely. The reason is that in acid rock drainage (a.k.a. acid mine drainage or AMD), the acidity is caused by sulfuric acid. Sulfuric acid, $\ce{H2SO4}$ is much less volatile than water. It simply won't appreciably evaporate from bulk liquids at normal conditions on the Earth. There ...

5

Aluminium oxide can be isolated from feldspar by first acid digestion with a mixture of hydrofluoric acid and sulfuric acid (get rid of silicon by formation of silicon tetrafluoride), then digesting the residue with sodium-potassium carbonate, dissolving the obtained mass in dilute hydrochloric acid and then precipitating $\ce{Al(OH)3}$ by adding ammonia. ...

5

The primary reason for this and other seemingly implausible features of element distribution is this: some elements are concentrated, and some are scattered. Strontium is much like calcium (which is way more abundant) and can hide as a tiny admixture in its minerals, while sulfur is pretty much on its own. Just think of the rare earth elements. Their name ...

5

There are two approaches to measuring kinetic isotope effects. One is to have two completely separate, isotopically pure systems, one heavy, and one light. In each system you can measure the rate of the reaction however you want. You don't have to be able to measure the rate in an "isotopically resolved" way, just measure the bulk rate. Each of your ...

4

Yes, I collect oxygen isotope data from plagioclase using the laser flourination method. To liberate the oxygen from the plagioclase, crystals are reacted with purified $\ce{BrF5}$. Then the plagioclase is hit with a $\ce{CO2}$ laser. Gasses are sent through a couple of cryogenic (liquid nitrogen) traps to filter, and then through a mercury diffusion pump to ...

4

In theory, yes it is possible. In practice, not really. First of all, the anorthite on the moon is never pure anorthite ($\ce{CaAl2Si2O8}$) but rather an anorthite-albite ($\ce{NaAlSi3O8}$) solid solution. That is, the single crystal contains both components. The diagram you added there, where it says "mole %"? The other stuff is albite. Now, back to glass ...

4

No, simmering sparkling water should have negligible effect on its mineral composition. You're exactly right that simmering it will drive off the $\ce{CO2}$. This $\ce{CO2}$ leaves as only/exactly $\ce{CO2}$ molecules, and any minerals that might have been associated with the carbonate/bicarbonate $(\ce{CO3^{2-}}/\ce{HCO3^-})$ will remain behind in the ...

4

Because dietary minerals are predominantly water soluble and not significantly soluble in fats, your first statement is correct; the minerals will not dissolve in the fats as you boil away the water. This is true even after all the water has boiled off, so the answer to your second question is no. As the water boils away, the minerals will precipitate out ...

4

Is there a chemical test for $\ce{[Si2O5]^2−}$ that can be done at home? First $\ce{[Si2O5]^2−}$ isn't a poly atomic ion like sulfate ($\ce{SO4-}$) or nitrate ($\ce{NO3}$) but represents a stoichiometry in the material. Unfortunately at this time a test without x-ray diffraction is not possible. Asbestos/chrystolite is not just a chemical formula, but a ...

4

As it's been stated in the comments, both formulas are equivalent, however, I'd like to clarify the terminology and use cases for both. $\ce{CaF2 * 3Ca3(PO4)2}$ is a formula of a formal addition compound (often used for clathrates, crystallohydrates and multiple salts). Widely used several decades ago when crystal structure of a given compound hasn't been ...

4

Fairly pure iron (or iron/nickel alloys) are found in meteoric iron. Some of these are surprisingly corrosion resistant... close to stainless steels. One well-known example is a dagger from Tutankhamun's tomb. See JSTOR for some more uses of meteoric iron. As for iron smelting, there is much information on the web, and I suggest you try some research.

4

It depends if the substance in bulk is transparent, highly reflective (metallic) or highly absorptive. Carbon in its graphite allotrope is highly absorptive, and even finely divided is still black. Carbon as diamond is transparent. Crushed diamonds are white -- look at a diamond file or abrasive disk. What happens is that incident light is scattered as it ...

4

What you're describing is essentially the field of "qualitative inorganic analysis". That's a very broad subject, but a short description is that prior to the advent of advanced instrumentation, chemists developed extensive series of tests specifically to determine the elemental composition of samples. For example, one would start with basic physical ...

3

If your sand is packed in a optimal sphere packing, like a hexagonal packing for example, nothing would happen to the sand level, because it can't be packed more dense. If the packing of the dry sand wasn't optimal (which it probably isn't 100%), then the water may help settle it through motion and friction and it would lower a bit. In any case it wouldn't ...

3

Some of the terms are pretty vague and it isn't worth getting hung up on a precise definition. Of the terms you use, "rock" is the vaguest. I means just about any hard thing you find in nature (and even that last qualification isn't precise as some people might call something like concrete an artificial rock). You can't infer anything much from the term "...

3

This is my pyrite right here. I got it from a jeweler. It is not dangerous to handle. However touching to much could cause it to lose its lust and shine. You could polish it with a polish rag to a tool that could remove rust. Again safe to handle just don't handle it to much

3

Pyrite does not turn into sulfuric acid. You can burn it with oxygen to give iron oxide and $\ce{SO2}$. $\ce{4 FeS2 + 11 O2 -> 2Fe2O3 + 8 SO2}$ $\ce{SO2}$ with water gives sulfurous acid. To really get sulfuric acid, $\ce{SO2}$ needs to be oxidised to $\ce{SO3}$ (Contact process), and then reacted with water. Actually with more sulfuric acid to give ...

3

Firstly the "correct" answer seems to be wrong, which is not an uncommon occurrence, so please do not always take answers at the back of books to be correct. Wikipedia lists the formula of beryl as $\ce{Be3Al2(SiO3)6}$ which is much more in accordance with what you have done. That aside, there are two things you need to correct. The percentages that you ...

3

It might be a lot harder than you think it is, because essentially every other element will influence crystal grow and purity. I found an interesting article by Esther García-Tuñón et. al., which is public access, outlining one of the possible routes to go. There might be more, but I am only using this as an illustrative example. Here is the ...

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