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Dissolving sand (or something similar) in a bottle of water? |
What is the electronic configuration of La⁺? |
Is it safe to treat platinum-carbon catalyst in an autoclave at 200 °C for 24 h in inert (nitrogen) atmosphere? If no, can you suggest safety measures? |
I wanted to figure out a way to make calcium metal with potassium oxide. $\ce{K2O}$ undergoes disproportionation at $\pu{350-430 °C}:$
$$\ce{2 K2O -> K2O2 + 2 K}$$
Now, if I mixed in $\ce{CaO}$ (1:2 molar ratio with $\ce{K2O})$ it would react with the potassium formed in the first reaction, forming calcium metal... |
How do we predict the products formed when we heat cyclic dicarboxylic acids? I know that in case of aliphatic dicarboxylic acids we apply Blanc's rule and predict the product formed based on the number of carbons between the acid groups.
In case of aliphatic dicarboxylic acids:
$$
\begin{array}{cc}
\hline
n ... |
T l, Dr: despite what you see from the aqueous electromotive series, potassium **does not** reduce calcium oxide in this setting.
You may be assuming that potassium, which lies above calcium in the electromotive series for aqueous solutions, therefore lies above calcium in all other settings regardless of chemical ... |
While performing flame tests for calcium fluoride and strontium fluoride, I observed strontium gives a long-lasting rose-red flame color but the brick red color for calcium quickly disappears. I also found some books mention the flame color for calcium as transient red.
Why does the flame color of calcium is transien... |
Flame Test: Why does the flame colour of calcium disappear quickly? |
You need (1) Any solid in powdered form (2) Recommended: Any other product that would change the nature of the solid to make it soluble in the solvent (let's inaccurately call it "solubility enhancer"), (3) Any solvent in which this solid would dissolve without producing gases or unsoluble co-products.
You would pic... |
Hydrogen iodide, $\ce{HI}$, is a dipolar molecule much larger than chlorine, $\ce{Cl2}$.
The melting point of $\ce{HI}\ (222.35 K)$ is definitely higher than that of $\ce{Cl2}\ (171.6 K)$. However, the boiling point of $\ce{HI}\ (237.79 K)$ is less than that of $\ce{Cl2}\ (239.11 K)$.
This is very confusing since... |
Hydrogen iodide, $\ce{HI}$, is a dipolar molecule much larger than chlorine, $\ce{Cl2}$.
The melting point of $\ce{HI}$ $(222.35\ \mathrm K)$ is definitely higher than that of $\ce{Cl2}$ $(171.6\ \mathrm K)$. However, the boiling point of $\ce{HI}$ $(237.79\ \mathrm K)$ is less than that of $\ce{Cl2}$ $(239.11\ \mat... |
To clarify: it sounds like you want a layer of *insoluble* sediment, so that if you shake the bottle, the water looks cloudy. Maybe it settles back out quickly, or maybe the water stays cloudy.
Then, you add something and shake the bottle again. This time, the sediment disappears.
There are *lots* of possibilitie... |
I was wondering if it was correct to calculate the gibbs free energy of reaction at P=1atm and T=1100K using the Jannaf thermochemical tables?
https://janaf.nist.gov/
For example for the reaction of ammonia and nitrous oxide:
NH3(g) + 1.5N2O(g)-> 2N2 (g) + 1.5H2O(g)
Can I later use this result to calculate the el... |
There are so many biological processes which are dependent upon ions of lighter metals (upper part of periodic table) such as K+, Na+, Mg2+ and even early transition elements (Fe, Mn, Cu, Ni) but I haven't yet come across dependence of biological phenomena on aluminium. Is it because there is less use of trivalence? Or... |
Why isn't aluminium involved in biological processes? |
I was wondering if it is correct to calculate the Gibbs free energy of reaction at $P = \pu{1 atm}$ and $T = \pu{1100 K}$ using the [NIST-JANAF thermochemical tables](https://janaf.nist.gov/). For example, for the reaction of ammonia and nitrous oxide:
$$\ce{NH3(g) + 1.5 N2O(g) -> 2 N2(g) + 1.5 H2O(g)}$$
Can I... |
One argument put forward has been that aluminum is very poorly bioavailable 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 ... |
One argument put forward has been that aluminum is very poorly bioavailable 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 ... |
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... |
> Do I use the total surface area of both Cathode and Anode or just Anode?
You use the cross-section, just like it were a wire.
> Cross-section of both Anode and Cathode or just Anode?
Just one. Like in a wire, you would measure the cross-sectional area once, not cut the wire into many piece and add up all th... |
Per industry literature i found that mineral oil is used to loosen out "super glue" and aid in removal from skin. I am exploring the chemistry of this loosening and i am intrigued. Please help me find which option applies here:
1. Does the mineral oil disturb the cohesive forces of the cured cyanoacrylate?
2. Does th... |
What's the mechanism behind mineral oil loosening cyanoacrylate bonds? |
Per industry literature I found that mineral oil is used to loosen out "super glue" and aid in removal from skin. I am exploring the chemistry of this loosening and I am intrigued. Please help me find which option applies here:
1. Does the mineral oil disturb the cohesive forces of the cured cyanoacrylate?
2. Does ... |
Glycoproteins come in O-linked and N-linked forms. For O-linked sugars, a glycosidic bond forms between the sugar and the hydroxyl of a serine or threonine side chain. For N-linked sugars, a glycosidic bond forms between the sugar and the amide of asparagine. The equilibrium for all these reactions lies on the side of ... |
Why is it that all biological molecules, which are mostly chiral are enantiomerically pure and in nature only one type of stereochemical structure is found. Because any other configuration would also have the same reactivity and only difference that they have this the angle of rotation of plane polarized light then why... |
Why are all biological molecules only exist as 1 enantiomer. Does it have any advantage? |
Compound P and compound Q are straight-chain constitutional (structural) isomers with the
molecular formula C5H12O. Compound P can form optical isomers, whereas compound Q
cannot.
When reacted with concentrated sulfuric acid, compound P forms two products, compounds
R and S; compound Q forms only one product, compo... |
Why does the $\ce{H-}$ ion in $\ce{LiAlH4}$ act as a nucleophile rather than a base in the reduction of carbonyl compounds ??
Because $\ce{H-}$ being a small ion would act as a better base than a nucleophile and I have been taught that it mostly acts as a base and it is very rarely that it is a nucleophile.
Also $\c... |
Why does the hydride ion in LAH act as a nucleophile rather than a base in the reduction of carbonyl compounds? |
why there is a change in enthalpy in phase transition?
as enthalpy depends only on temp, dH=cp×dT , and the change in temperature is dT=0?
|
why enthalpy change in phase transition when there is no change of temperature? |
I know that this is a very basic question, but I am new to chemistry and I cannot figure it out on my own:
A combustion is always exothermic, so ΔH is negative. It says in my textbook that more stable molecules have a lower heat of combustion (I am assuming here that this is basically identical to stating that it ha... |
I will need a fluid around $3\space mPa\cdot s$. Is there any fluid you recommend near this or any solute-solvent combination at a specific concentration? |
What is prefix L for amino acids? |
I am new to organic chemistry and am confused regarding the following question:
Does the geometrical isomerism of 3-methyl-2-heptene fall into the category of trans vs. cis, or the category of Z vs. E? And what is the rule that determines whether it falls into the first or the second category?
My textbook is not ... |
I want to know if someone has supporting tips or solutions to my problem:
In biotechnology, fermentations are used to grow microorganisms. These need a specific media/broth in which temperature, pH, substrate and many other factors conclude to an optimum. Only if the surrounding broth is in optimal condition for the i... |
I want to know if someone has supporting tips or solutions to my problem:
In biotechnology, fermentations are used to grow microorganisms. These need a specific media/broth in which temperature, pH, substrate and many other factors conclude to an optimum. Only if the surrounding broth is in optimal condition for the i... |
> 1.) So is iron the only element that can do that? If not, what is it about iron that makes it the only element found in hemoglobin?
No, iron is not the only metal that will fit inside the porphyrin structure. But its ability to be an electron acceptor and donor makes it very useful for oxygen and carbon dioxide to... |
Why there is a change in enthalpy in phase transition?
I'm asking because enthalpy depends only on temperature:
$$\mathrm dH = C_p\,\mathrm dT,$$
and the change in temperature is $\mathrm dT = 0.$
|
Why enthalpy changes in phase transition when there is no change of temperature? |
Is there an easy way to detect methanol in spirits, which, you suspect, may have been adulterated?
Thanks in advance for your help.
-Simon |
Is there an easy way to detect methanol in spirits (which may have been adulterated)? |
There are so many biological processes which are dependent upon ions of lighter metals (upper part of periodic table) such as $\ce{K+}$, $\ce{Na+}$, $\ce{Mg2+}$ and even early transition elements ($\ce{Fe}$, $\ce{Mn}$, $\ce{Cu}$, $\ce{Ni}$), but I haven't yet come across dependence of biological phenomena on aluminium.... |
I want to know if someone has supporting tips or solutions to my problem:
In biotechnology, fermentations are used to grow microorganisms. These need a specific media/broth in which temperature, pH, substrate and many other factors conclude to an optimum. Only if the surrounding broth is in optimal condition for the i... |
Greetings fellow chemists!
I am thinking on an alternative synthesis of pPDA, in wich i need counsel. I was thinking about these easy reactions, and i want to ask if it can be done, or maybe you can hint me some reference. I am trough the reading of nitration and reduction of aniline, or from 4-nitrochlorobenzene or... |
There are so many biological processes which are dependent upon ions of lighter metals (upper part of periodic table) such as $\ce{K+}$, $\ce{Na+}$, $\ce{Mg^{2+}}$ and even early transition elements ($\ce{Fe}$, $\ce{Mn}$, $\ce{Cu}$, $\ce{Ni}$), but I haven't yet come across dependence of biological phenomena on alumini... |
> For the galvanic cell $$\ce{Ag\vert AgCl(s) , KCl}(0.2M) \vert \vert \ce{KBr}(0.001M ),\ce{AgBr(s)\vert Ag }$$
>Find the EMF generated , given $K_{sp} AgBr = 2.8× 10 ^{-10} , K_{sp} AgCl = 3.3× 10 ^{-13} $
This is the question from JEE exam (1992).
The $E^°$ of individual half reactions is not given, but then ho... |
How to solve this nerst equation without E° ?? With 2 Metal-Metal Insoluble salt type electrodes of AgCl and AgBr |
First, I'll go ahead and say I'm not very versed in chemistry. My question comes from my interest in planetary-sciences, specifically the speculation that there are likely exoplanets and moons with surface oceans of water-ammonia oceans. However I can't find much hard info on how a vast body (i.e. ocean) of water-ammon... |
How Would A Vast Mixture (Like an Ocean) of Ammonia-Water Behave in Terms of Evaporation and Freezing? |
> For the galvanic cell
> $$\ce{Ag | AgCl(s), KCl (\pu{0.2 M}) || KBr (\pu{0.001 M}), AgBr(s) | Ag}$$
> find the EMF generated given $K_\mathrm{sp}(\ce{AgBr}) = \pu{2.8e-10},$ $K_\mathrm{sp}(\ce{AgCl}) = \pu{3.3e-13}.$
This is the question from JEE exam (1992).
How to start solving the problem since the $E... |
First, I'll go ahead and say I'm not very versed in chemistry. My question comes from my interest in planetary-sciences, specifically the speculation that there are likely exoplanets and moons with surface oceans of water-ammonia. However I can't find much hard info on how a vast body (i.e. ocean) of water-ammonia woul... |
I'd say the suggested reaction of benzene-1,4-diol (hydroquinone) with $\ce{PCl3}$ to get 1,4-dichlorobenzene would not work (see Waylander's comment). However, you can buy 1,4-dichlorobenzene very cheap (*e.g.*, USD 21.50 for $\pu{100 g}$ bottle from Sigma-Aldrich) so why you need this trouble?
The suggested react... |
I am thinking on an alternative synthesis of pPDA, in which I need counsel. I was thinking about these easy reactions, and I want to ask if it can be done, or maybe you can hint me some reference. I am trough the reading of nitration and reduction of aniline, or from 4-nitrochlorobenzene or the DuPont synthesis.
[![... |
Is there an easy way to detect methanol in spirits, which, you suspect, may have been adulterated? |
How would we know if a salt such as $\ce{CO_2}$ reacts acidic or basic in water.
The explanation I see everywhere is that you have to see the acid and base that makes up the salt, in the case of $\ce{NH_4Cl}$ it would be a weak base and strong acid making the solution acidic, but is there a better theory for that?
... |
Does the salt react basic or acidic? |
Why is it that chiral biological molecules are enantiomerically pure? The other enantiomer would have the same reactivity, and the only difference is their angle of rotation of plane polarized light. Why, then, is one enantiomer preferred over the other?
Is it that the enantiomer found in our bodies has some advant... |
Why do chiral biological molecules only exist as one enantiomer? Does it have any advantage? |
>Are all the biochemicals that our body uses enantiomerically pure or are racemic mixtures too?
Many molecules exist in both forms in nature. One fun example are the enantiomeric terpenoids R-(–)-carvone and S-(+)-carvone. The R-form smells like spearmint while the S-form smells like caraway. The difference in smell... |
>Are all the biochemicals that our body uses enantiomerically pure or are racemic mixtures too?
Many molecules exist in both forms in nature. One fun example are the enantiomeric terpenoids R-(–)-carvone and S-(+)-carvone. The R-form smells like spearmint while the S-form smells like caraway. The difference in smell... |
> How to start solving the problem since the $E^\circ$ of individual half reactions is not given?
This is a concentration cell, i.e. the half reactions at the anode and at the cathode are the same (except for the direction). The standard reduction potentials will cancel out, i.e. $E^\circ (\mathrm{cell}) = 0$. |
> How to start solving the problem since the $E^\circ$ of individual half reactions is not given?
This is a concentration cell, i.e. the half reactions at the anode and at the cathode are the same (except for the direction).
**AgCl(s) electrode**
$$\ce{Ag(s) -> Ag+(aq) + e-}$$
$$\ce{Ag+(aq) + Cl-(aq) <=> AgCl(... |
How predict whether a salt will act as an acid or as a base in aqueous medium? |
How to would we know if a salt such as $\ce{CO_2}$ reacts acidic or basic in water.
The explanation I see everywhere is that you have to see the acid and base that makes up the salt, in the case of $\ce{NH_4Cl}$ it would be a weak base and strong acid making the solution acidic, but is there a better theory for that... |
> For the galvanic cell
> $$\ce{Ag | AgCl(s), KCl (\pu{0.2 M}) || KBr (\pu{0.001 M}), AgBr(s) | Ag}$$
> find the EMF generated given $K_\mathrm{sp}(\ce{AgCl}) = \pu{2.8e-10},$ $K_\mathrm{sp}(\ce{AgBr}) = \pu{3.3e-13}.$
This is the question from JEE exam (1992).
How to start solving the problem since the $E... |
How to predict whether a salt will act as an acid or as a base in aqueous medium? |
> How to start solving the problem since the $E^\circ$ of individual half reactions is not given?
This is a concentration cell, i.e. the half reactions at the anode and at the cathode are the same (except for the direction).
**AgCl(s) electrode**
$$\ce{AgCl(s) <=> Ag+(aq) + Cl-(aq)}$$
$$\ce{Ag+(aq) + e- -> Ag(... |
> How to start solving the problem since the $E^\circ$ of individual half reactions is not given?
This is a concentration cell, i.e. the half reactions at the anode and at the cathode are the same (except for the direction).
**AgCl(s) electrode**
$$\ce{AgCl(s) <=> Ag+(aq) + Cl-(aq)}$$
$$\ce{Ag+(aq) + e- -> Ag(... |
> How to start solving the problem since the $E^\circ$ of individual half reactions is not given?
This is a concentration cell, i.e. the half reactions at the anode and at the cathode are the same (except for the direction).
**AgCl(s) electrode**
$$\ce{AgCl(s) <=> Ag+(aq) + Cl-(aq)}$$
$$\ce{Ag+(aq) + e- -> Ag(... |
I'm part of a rocket buiding team and i'm working with propellants. We use saltpeter as the oxidizer, bought as fertilizer and purified by recrystallization. Recently we bought it from another source, that identified the chemical as potassium nitrate, as usual, but when we heated it to make the propellant it simply mel... |
> How to start solving the problem since the $E^\circ$ of individual half reactions is not given?
This is a concentration cell, i.e. the half reactions at the anode and at the cathode are the same (except for the direction).
**AgCl(s) electrode**
$$\ce{AgCl(s) <=> Ag+(aq) + Cl-(aq)}$$
$$\ce{Ag+(aq) + e- -> Ag(... |
> How to start solving the problem since the $E^\circ$ of individual half reactions is not given?
This is a concentration cell, i.e. the half reactions at the anode and at the cathode are the same (except for the direction).
**AgCl(s) electrode**
$$\ce{AgCl(s) <=> Ag+(aq) + Cl-(aq)}$$
$$\ce{Ag+(aq) + e- -> Ag(... |
Even though this question 1) has an answer with multiple upvotes (and I was the first upvote), 2) the OP has accepted the answer and 3) I have great respect for @Karsten Theis, having co-taught a quant class with him back in 2008 and knowing, first hand, that he is an excellent scientist and teacher, nonetheless, I hav... |
Even though this question 1) has an answer with multiple upvotes (and I was the first upvote), 2) the OP has accepted the answer and 3) I have great respect for @Karsten Theis, having co-taught a quant class with him back in 2008 and knowing, first hand, that he is an excellent scientist and teacher, nonetheless, I hav... |
What ratio of bicarb to sugarcane juice with a pH level of 4.5-5.5 to neutralize pH level? |
> How to start solving the problem since the $E^\circ$ of individual half reactions is not given?
This is a concentration cell, i.e. the half reactions at the anode and at the cathode are the same (except for the direction).
**AgCl(s) electrode**
$$\ce{AgCl(s) <=> Ag+(aq) + Cl-(aq)}$$
$$\ce{Ag+(aq) + e- -> Ag(... |
Both fatty acid and polyethylene are made (mostly) of carbons with hydrogens with a very similar configuration, yet, their properties are very different. What am I missing? |
$\ce {[Al(H2O)6]^3+}$ is a well-known complex ion formed by the $\ce {Al^3+}$. I have always had the understanding that only the aqua complexes of transition metal ions, such as $\ce {[Fe(H2O)6]^3+}$, would legitimately possess dative covalent bonding between the water ligands and the central metal ion. I had always th... |
I'm trying to figure out the isomeric products of the radical monobromination of bicyclo[2.2.1] heptane. I'm not sure at which site the bromination would happen and what makes one site better than the other (how can one determine this without given the reaction enthalpy ?). I was also given the hint that there are ster... |
I am fairly new to anodization of Titanium. It concerns anodization using oxalic acid with the sole purpose of coloring Titanium grade 2 parts (= type III?). After some research online, I found a lot of information on the required voltage levels per color. However, to my understanding, the "purpose" of the voltage is o... |
By exporting some search results from Reaxys, I found "Reaction rank" to be one of the columns in the Excel file. In my file, values descend from 107 to 52 and skip some value in-between too. Does anyone know what reaction rank stands for here? |
What does "reaction rank" in Reaxys stand for? |
I am thinking on an alternative synthesis of pPDA, in which I need counsel. I was thinking about these easy reactions, and I want to ask if it can be done, or maybe you can hint me some reference. I am trough the reading of nitration and reduction of aniline, or from 4-nitrochlorobenzene or the DuPont synthesis.
[ patent, a synthetic p... |
My question is regarding Swern oxidation. Why is the methyl group of the DMSO deprotonated and not directly the red hydrogen atom of the R2-CH-O Bond deprotonated? Shouldnt it be that Oxygen more electronegative ( stronger -I effect) than sulfur and shouldnt that make that corresponding hydrogen atom more acidic? Or is... |
First, I'll go ahead and say I'm not very versed in chemistry. My question comes from my interest in planetary-sciences, specifically the speculation that there are likely exoplanets and moons with surface oceans of water-ammonia. However I can't find much hard info on how a vast body (i.e. ocean) of water-ammonia woul... |
I am confident enough about my knowledge about spiking and the process of standard addition but I came across this process which claimed to have a percent recovery of 115% and it was considered as a good recovery process. How it is considered a good recovery? Is it because you add too much of the spike and recovered mo... |
How can spike recovery be over 100% for a good recovery process? |
When beryllium is bombarded with alpha particles, where do the electrons come from to make the carbon stable?
[![enter image description here][1]][1]
Source: https://en.wikipedia.org/wiki/Triple-alpha_process
[1]: https://i.stack.imgur.com/0IegI.png |
> When beryllium is bombarded with alpha particles, where do the electrons come from to make the carbon stable?
Nowhere. This is a *nuclear* reaction, not a chemical one. Charge is conserved and no extra electrons were supplied.
The carbon *nucleus* is stable with respect to nuclear decay.
Chemical stability... |
I was trying to calculate amount of salt needed to lower the melting point of water by 5°C. According to my solutions, I need to make sure $$n*pot(Water, solid) =n*pot(Water, liquid)+ RT \cdot ln(x)$$,x being $ \frac{n}{n+2m}$
I however thought that I need to make sure that
$$n*pot(Water, solid) + m*pot(NaCl, sol... |
Why do we use hydrochloric in the test for sulfate ions but nitric acid for halide ions? |
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