31

In my opinion, the catalytic, solar-driven conversion of carbon dioxide to methanol, formic acid, etc. is much more interesting and promising, but since Enrico asked for the conversion of carbon dioxide to carbon itself: The group around Yutaka Tamaura was/is active in this field. In one of their earlier publications,[1] they heated magnetite ($\ce{Fe3O4}$) ...


20

Chemicals cupboard often produce quite extraordinary reactions, much like hospitals are home to some unusual and severe infections. Nitric acid does not normally exhibit such a bizarre behavior. Yet in your case it did. How so? My bet is on some unknown additional component which came from the same cupboard, but from a different bottle. For instance, it ...


13

Reaction conditions As Watts et al. have shown, the decomposition products of this Fenton-like reaction strongly depend on the $\mathrm{pH}$ of the solution.1 If performed in acidic conditions, the reaction generates mostly hydroxy radicals, but no reductants (which would be the hydroperoxide and superoxide anions). If, conversely, the reaction is held in ...


11

There are several mentions of this on the interwebs, including this one on a science forum. The consensus is ammonium nitrate. From working with the stuff and inheriting old bottle in schools, I have seen this a number of times. The fine crystal certainly looks like slow growth from airborne NH3 or amines as the other post said, but NH3 is far more common, ...


11

Theoretically, it will decompose, but the reaction is rather slow, on a human timescale. One experiment ran for almost forty years (J. Phys. Chem. 1958, 62 (3), 360–361), from 1918 to 1957, without noticeable decomposition. That said, in aqueous solutions it breaks down more rapidly. In vivo, the half-life is a few seconds. It is amazing to me that a free ...


11

Chemistry, despite being several hundred year old science, it is still very much empirical. In the beginning you will have to learn and accept some facts. Later you will start to see patterns (hence the periodic table). If you learn that the carbonate of barium decomposes into carbon dioxide and barium oxide, it will be safe to say that Mg, Ca, Ba, Sr, will ...


10

No. Radioactivity means that the nucleus of a particular atom is unstable, and the nucleus will decay to a more stable state either by decomposing or emitting energy (as a photon). This instability will not make other nuclei unstable unless the decay of one of the radioactive atoms causes a fission process in one of the atoms in the desk. This is a secondary ...


9

Electrolysis of carbonates in anhydrous environment can produce either $\ce{CO + O_2}$ or $\ce{C + O_2}$, [ref] depending on conditions. A base, remaining in electrolyzed liquid then can capture carbon dioxide from other sources and be recirculated. Reference: L. Massot, P. Chamelot, F. Bouyer, P. Taxil; Electrodeposition of carbon films from molten ...


9

One can rarely tell a priori what the steps are, and the results obtained experimentally may seem not intuitive at all if one tries to deduce the dehydration steps solely from the crystal structure (e.g. from the arrangement of the aqua ligands and water molecules trapped within the crystal lattice).¹ TG-DTG-DTA techniques, often coupled with powder XRD, ...


9

In appears that the synthetic procedure for preparation of iron(II) oxide from iron(II) oxalate has been first described by Günther et al. [1] and subsequently summarized in Brauer's Handbook of Preparative Inorganic Chemistry [2, p. 1497]: Iron (II) Oxide I. $$\ce{\underset{143.8}{FeC2O4} = \underset{71.8}{FeO} + \underset{28.0}{CO} + \underset{...


8

Stability, the thermodynamic property, is defined as whether a decomposition reaction is exergonic or endergonic at a certain temperature. The reaction $\ce{CaO -> Ca + 1/2 O2}$ is endergonic across a very large temperature range. But that doesn’t necessarily help you. In that list of four, we have to clearly molecular compounds and two mostly ionic ones....


7

Use Exploit the fact that burning magnesium continues to burn in atmosphere of carbon dioxide. $${\ce{Mg}}+\color{\red}{\ce{CO2}}\to \ce{MgO}+\color{\red}{\ce{C}} $$ Now you can electrolyse your mixture : $$\ce{MgO}+\ce{H2O}\to \ce{Mg(OH)2} $$ $$\ce{4OH-}\to\color{\red}{\ce{ O2}}+\ce{2H2O}+\ce{4e-}$$


6

To clear up what are becoming confusing comments. An atom is a nucleus of protons and neutrons surrounded by electrons. An atom can decay by fission to make two or more atoms with a smaller number of protons and neutrons in each new atom. The electrons get distributed between them. Now in physics we'd normally describe this as a nuclear decay, rather ...


6

I am adding a more recent study to complement the answer given by tschoppi. This journal addresses the kinetics and mechanism for the decompostion of $\ce{H2O2}$ on transition metal oxide surfaces. However, the paper only considers $\ce{ZrO2}$, $\ce{TiO2}$, $\ce{Y2O3}$. Although $\ce{MnO2}$ is also a transition metal oxide, $\ce{MnO2}$ may be different ...


5

I don't understand why calcium carbonate decomposes... It's not soluble in water. It's more soluble in water than you might think. If it weren't soluble, we wouldn't have awesome things such as stalagmites in caves. Calcium sulfate is more soluble in water than the carbonate, but that isn't saying much. It's solubility is only about $\pu{2 g/L}$. So ...


5

When it comes to non-molecular solids such as glass, metal or diamond, "a single entity" is in fact the formula unit, the concept identical to a "molecule" for, well, molecular compounds. Both formula unit and molecule are the smallest portion of a substance that preserves its chemical properties. As long as the formula unit remains the same, there is no ...


5

You don't have to reinvent the wheel. Food industry already uses quite simple oxygen scavengers for decades, and one of the most affordable formulations include iron powder mixed with sodium chloride. Typically, an oxygen scavenger is packaged in small packets (sometimes labeled as "oxygen absorber" or "antioxidant") that are added with the product inside ...


5

This question serves as a prime example of how much fake and scientifically incorrect information, or more famously, fake news is there on the web. This is why ordinary web should not be anyone's first priority to search about scientific topics. There is a famous saying that "paper never refused an ink" which applies to the web as well in the sense that ...


4

Acetic acid (as an example of a typical carboxylic acid) reacts with calcium hydroxide to form calcium acetate. This is a simple acid-base reaction which forms a salt and water: $$\ce{2CH3COOH + Ca(OH)2 -> (CH3COO)2Ca + 2H2O}$$ Upon heating, calcium acetate undergoes decomposition to acetone and calcium carbonate. The acetone can be distilled off from ...


4

Nerve agents are usually susceptible to hydrolysis leading to non-toxic degradation products Most modern nerve agents are based on fluorophosphonate cores. That is they contain a $\ce{PFO(OR)(X)}$ core where R is some organic radical (-iPr in sarin) and X can be a range of radicals (Me- in sarin, OR or N=R in novichok agents). Most are not very stable in ...


4

Have you checked Wikipedia? Upon thermal decomposition, $\ce{LiNO3}$ gives lithium oxide ($\ce{Li2O}$), nitrogen dioxide, and oxygen: $$\ce{4 LiNO3 → 2 Li2O + 4 NO2 + O2}$$ Other group I nitrates decompose differently, forming the nitrite salt and oxygen. Because of its relatively small size, the lithium cation is very polarizing, which ...


4

In the solid state of ammonium chloride, the nitrogen and hydrogen atoms are connected by covalent bonds, forming the ammonium ion. The bond length is about 98 pm. Each ammonium ion is surrounded by eight chloride ions (and in turn, each chloride ion is surrounded by eight ammonium ions). The distance between a chloride and the closest hydrogen atoms is ...


4

1.20g of hydrated tin chloride decompose to form 1.01g of anhydrous tin chloride on heating. Calculate the value of x 1.20 Stannous chloride hydrate = 1.01 anhydrous stannous chloride So 1.20 - 1.01 = 0.19 grams of water Moles of anhydrous stannous chloride $$\dfrac{1.01}{189.60} = 0.0053270$$ Moles of water $$\dfrac{0.19}{18} = 0.01065$$ ratio of ...


4

Biologically, methane is produced by methanogens, which are Archeabacteria. They do not utilize carbohydrates such as cellulose or glucose directly. Instead, they typically consume acetate or a mixture of hydrogen gas and carbon dioxide. These stoichiometry of these two processes is $\ce{4H2 + CO2 -> CH4 + 2H2O}$ or $\ce{CH3C(O)OH -> CH4 + CO2}$. To ...


4

Chemical reactions in which, a single substance splits up into two or more simpler substances are called decomposition reactions. These reactions are carried out by energy, supplied by different sources. The required energy can be supplied by heat (thermolysis), electricity (electrolysis), or light (photolysis). Let’s talk about photolysis reactions (not ...


3

You actually can get lithium nitrite from the nitrate by controlling the decomposition temperature around 500°C. But yes, as Nilay points out the nitrite is more prone to decomposing further than sodium nitrite because of the polarizing power of the lithium cation.


3

The photodisintegration of $\ce{^{9}_{4}Be}$ might come close to what you are looking for. When high energy photons excite a beryllium-9 nucleus it may decay into a neutron and two helium-4 nuclei ($\alpha$ particles). Neglecting the neutron, the latter are roughly half of the original nucleus. $$\ce{^{9}_{4}Be + \gamma -> 2 ^{4}_{2}He} + n$$


3

Often in chemistry "facts" depend on perspective. You're right that essentially H goes from -1 to 0 and As from 3+ to 0. But in general redox reaction involve two different chemical species. In this case it is better to think of the reaction as a decomposition reaction rather than a redox reaction.


3

There is nothing magical about light; it just brings in some energy. What's important is that it brings a huge lump of energy to one point, at once. If you'll heat the system in the hope that the heat will provide the necessary energy for the reaction, then you might or might not succeed. In the worst case, before initiating your reaction, heat will initiate ...


Only top voted, non community-wiki answers of a minimum length are eligible