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What is octanamide used for? |
how would we use our pKa of the acid component of the buffer to calculate [A^-1]/[HA]
I know pH=pKa + log10([A^-1]/[HA]) rearranging gives me log10([A^-1]/[HA])=pH-pKa
if for example the pH=4.5, pKa pf acid=3.74
is it correct to say
[A^-1]/[HA]=19/250
since log10([A^-1]/[HA])=pH-pKa
=log10([A^-1]/[HA])=4.... |
I read a paper about [enzyme-catalysed synthesis of octanamide](http://dx.doi.org/10.1039/C39930001831).
What is octanamide used for? |
I read about Perchloride in a talk and after trying to search for its chemical equation, the search results imply that Perchloride is actually named Perchlorate. is this correct? |
is Perchloride the same as Perchlorate? |
In [an article][1] I am trying to understand the following occurs:
>Synthesis of octahedral $\ce{Cu_2O}$ seeds:In a typical synthesis, 2.9946 g of $\ce{Cu(CH_3COO)_2}$ was dissolved in deionizedwater (20 mL) using a beaker under a constant stirring at 70°C for 2 min. A dark precipitate was produced when a sodium hy... |
How would we use our $\text{pKa}$ of the acid component of the buffer to calculate $\dfrac{[\ce{A}^{-}]}{[\ce{HA}]}$?
I know $$\text{pH = pKa} + \log_{10}\left(\dfrac{\ce{[A^{-}]}}{[\ce{HA}]}\right)$$ rearranging gives me $$\log_{10}\left(\dfrac{\ce{[A^{-}]}}{[\ce{HA}]}\right)=\text{pH - pKa}$$
if for example the... |
I've read that when a carboxylic acid reacts with LiAlH4 it gives two alcohols (just like an ester).
But when I try to think of the mechanism, I get stuck here:
LiAlH4 produces H-, since H- is a strong base it should immediately abstract a proton from carboxylic acid to give the corresponding carboxylate ion (Jus... |
I've read that when a carboxylic acid reacts with $\ce{LiAlH_4}$ it gives two alcohols (just like an ester).
But when I try to think of the mechanism, I get stuck here:
$\ce{LiAlH_4}$ produces $\ce{H^-}$, since $\ce{H^-}$ is a strong base it should immediately abstract a proton from carboxylic acid to give the co... |
First, as kaliaden commented, the true equilibrium constant
$$K(T,p) = a(\textrm{CaO,s}) a(\textrm{CO$_2$,g}) / a(\textrm{CaCO$_3$,s}) \approx
p_\textrm{CO$_2$} / p^\circ \equiv K_p(T)$$
where $a$ are the activities, $p$ the partial pressure and $p^\circ$ is one bar.
Thus $K$ basically only depends on temperatu... |
Consider a one dimensional predominance diagram for a simple acid-base reaction:
$$AH = A^- + H^+$$
With equilibrium constant:
$$K_a = \frac{[A^-]_{eq}[H^+]_{eq}}{[AH]_{eq}}$$
If I understand correctly, $[H^+] > K_a$, then $[AH]>[A^-]$. At first I thought I understood why this was so: the $[H^+]$ cancels ou... |
In [Las Palmas de Gran Canaria][2], tap water is chlorinated. In an Internet forum, someone [claims][1] that in 2008 the water had a chlorine concentration of 0,5 - 1mg/l. On the [official site][3] of Emalsa, the water provider, I couldn't find any information about chlorine concentration. I tried contacting them onl... |
How much ascorbate to neutralize one liter of chlorinated tap water? |
In [Las Palmas de Gran Canaria][2], tap water is chlorinated. In an Internet forum, someone [claims][1] that in 2008 the water had a chlorine concentration of 0,5 - 1mg/l. On the [official site][3] of Emalsa, the water provider, I couldn't find any information about chlorine concentration. I tried contacting them onl... |
In my introductory chemistry course, we learned that for reversible processes, entropy is defined delta S = q/T. However, we did not spend that long on this before moving on to other things like gibbs free energy. My questions are: (1) what exactly is a reversible process and (2) why must we use things like standard mo... |
This is just a very short explanatory note on [the article suggested by Greg E.][1].
The reaction between ascorbic acid and hypochlorous acid is as follows:
$$ \ce{C5H5O5CH2OH + HOCl → C5H3O5CH2OH + HCl + H2O}$$
so for 1 mole of hypochlorous acid you need 1 mole of ascorbic acid. This can be recalculated into a ma... |
In my introductory chemistry course, we learned that for reversible processes, entropy is defined $ΔS = Q/T$. However, we did not spend that long on this before moving on to other things like gibbs free energy. My questions are:
<br>1. What exactly is a reversible process?
<br>2. Why must we use things like standard... |
Consider a one dimensional predominance diagram for a simple acid-base reaction:
$$AH \rightleftharpoons A^- + H^+$$
With equilibrium constant:
$$K_a = \frac{[A^-]_{eq}[H^+]_{eq}}{[AH]_{eq}}$$
If I understand correctly, $[H^+] > K_a$, then $[AH]>[A^-]$. At first I thought I understood why this was so: the $... |
Consider a one dimensional predominance diagram for a simple acid-base reaction:
$$\ce{AH <=> A^- + H^+}$$
With equilibrium constant:
$$K_a = \frac{[A^-]_{eq}[H^+]_{eq}}{[AH]_{eq}}$$
If I understand correctly, $[H^+] > K_a$, then $[AH]>[A^-]$. At first I thought I understood why this was so: the $[H^+]$ can... |
I am currently researching as too which is better for maintaining the chemical balance in a swimming pool. I have obviously tried the standard Google search for `Salt Water or Chlorinated Pools` and have come up with lots of results. The only problem, is that most of these results are based more around peoples opinions... |
Chemical reasons for choosing Salt Water or Chlorinated pool? |
To me it seems like diatomic elements like F2, Cl2, etc. occur more prevalently than diatomic molecules with both, like ClF.
Is this the case, and if so, what causes diatomic elements to be favored? |
Do halogens bond more commonly with each other or themselves? |
In my introductory chemistry course, we learned that for reversible processes, entropy is defined as $ΔS = q/T$. However, we did not spend that long on this before moving on to other things like Gibbs free energy. My questions are:
<br>1. What exactly is a reversible process?
<br>2. Why must we use things like stand... |
To me it seems like diatomic elements like $\ce{F2}$, $\ce{Cl2}$, etc. occur more prevalently than diatomic molecules with both, like $\ce{ClF}$.
Is this the case, and if so, what causes diatomic elements to be favored? |
Does there exist a formula I can use to calculate alcohol content of a solution after heating it for some time?
I have the following use-case:
I am making a pecan pie. I have a thick sugary solution. I am not sure how much the makeup of the solution matters. Just assume its more viscous than water. I add 75 ML of 8... |
Does there exist a formula I can use to calculate alcohol content of a solution after heating it for some time?
I have the following use-case:
I am making a pecan pie. I have a thick sugary solution. I am not sure how much the makeup of the solution matters. Just assume its more viscous than water. I add 75 ML of 8... |
>Why don't we need to consider about the $H^+$ ions of water when finding the pH of 0.01M of HCl solution?
The pH value of something is depends on the molarity of $H^+$ ions. But the teachers say the calculation is just $-\log(0.01)$, don't we need to consider about the $H^+$ ions of water? Thanks. |
Does there exist a formula I can use to calculate alcohol content of a solution after heating it for some time?
I have the following use-case:
I am making a pecan pie. I have a thick sugary solution. I am not sure how much the makeup of the solution matters. Just assume its more viscous than water. I add 75 ml of 4... |
You could consider them, but what would be the result?
$0.01 M$ of $\ce{HCl}$ with $1\times10^-7 M$ of $\ce{H^+}$ from water gives you $0.0100001 M$ of $H^+$. Find the pH of this concentration of $\ce{H^+}$ and compare with the pH you would obtained if you used $0.01 M$ directly.
You shouldn't see that the result... |
For a pure substance, to be able to calculate how much has boiled off after $N$ minutes you will need the [enthalpy of vaporization][1], $L$ (in kJ/kg) and the heat input, $Q$ (in kJ) which will give you:
$$\tag{1} m=\frac{\epsilon \, Q}{L}$$
where $m$ is the mass that has boiled off and $\epsilon$ is the fraction of... |
What are the main axis of research in Chemistry? |
Chemistry is the study of the transformation of matter. People are studying every single aspect of how this happens.
You can't get a simple answer for this question. For example, if you were to ask, "what are the important aspects of chemistry research?" You might get back drug design, nanotechnology, etc. etc. B... |
Electron affinity of chlorine = -349 kJ per mole. And, first ionization energy of sodium = 496 kJ per mole while energy required for combining= 147 kJ per mole.
Isn't it a contradiction against genereal physics and G.N. Lewis' "electronic theory of valency"?
|
Does there exist a formula I can use to calculate alcohol content of a solution after heating it for some time?
I have the following use-case:
I am making a pecan pie. I have a thick sugary solution. I am not sure how much the makeup of the solution matters. Just assume its more viscous than water. I add 75 ml of 4... |
You could consider them, but what would be the result?
$0.01 M$ of $\ce{HCl}$ with $1\times10^{-7} M$ of $\ce{H^+}$ from water gives you $0.0100001 M$ of $H^+$. Find the pH of this concentration of $\ce{H^+}$ and compare with the pH you would obtain if you used $0.01 M$ directly.
You shouldn't see that the result... |
I want to understand the degradation mechanism of [hydroxymethylfurfural (HMF)](http://en.wikipedia.org/wiki/Hydroxymethylfurfural). According to the Wikipedia article, HMF is degraded in honey. Someone said that the degradation proceeds via **2** possible routes and that the products are 2,5-dioxo-3-hexenal and [4-oxo... |
Even though I voted to close this question as not constructive, these are among the most important unsolved problems in chemistry:
1. Liquid Water - We still know so little about the molecular level interactions of water molecules with themselves and other species. The great extent of [hydrogen bonding][1] networks ... |
Why are the vinylic bonds in alkenes slightly polar? |
This is for determination of copper in a penny Lab. After making standard solutions we made a solution with a penny, dissolving it in nitric acid and adding ammonium hydroxide to form a more absorbtive copper complex. We didn't control the amount of ammonium hydroxide used in our samples.
How can I test whether or not... |
How do I know if concentration of Ammonia affected my absorbency measurements? |
Do note, however, that the self-ionization of water technically must be taken into account. Though very often justifiable, it is an *approximation* to leave it out. Ask yourself, what is the pH of a $10^{-8}\ mol.L^{-1}$ solution of $\ce{HCl}$? It doesn't make sense to add a strong acid to pure water, however dilute, ... |
The justification or rather intuition behind Markownikoff's rule is the stability of intermediate carbocation. The more substituted the carbocation the more stable the product. But based on this ideas how can we satisfactorily explain the following reaction?
$$vinyl chloride+HCl=CH_2-CHCl_2$$?? |
Markownikoff's addition to halogenated alkene? |
The justification or rather intuition behind Markownikoff's rule is the stability of intermediate carbocation. The more substituted the carbocation the more stable the product. But based on this ideas how can we satisfactorily explain the following reaction?
$$\ce{CH2=CHCl + HCl -> CH3-CHCl2}$$ |
[Markovnikov's rule][1] is usually stated in terms of subsitution on the alkene, for example:
> In the addition of HX to an alkene, the hydrogen atom always attaches at the less substituted carbon atom (the carbon atom which already has more hydrogen atoms).
This version of the rule works well most of the time. I... |
I have a formulae
Acid: na = [HA].Va=0.1.Va=
Base: nb = [HA].Vb=0.1.vb=
and I need to calculate the amount of acid and base in 15ml of the buffer, which I worked out to equal
Va=9.7ml
Vb=5.3ml
how would I start this question? what is HA? I ony have [A^-]/[HA]= 0.5495
why does it tell me nb = [HA].Vb=0.1.vb mea... |
I have a formulae:
Acid: $n_a = [\ce{HA}].V_a=0.1.V_a$
Base: $n_b = [\ce{HA}].V_b=0.1.V_b$
and I need to calculate the amount of acid and base in $15ml$ of the buffer, which I worked out to equal
$V_a=9.7ml$
$V_b=5.3ml$
How would I start this question? What is $\ce{HA}$? I only have $\dfrac{[A^-]}{[HA... |
I have a formulae:
Acid: $n_a = [\ce{HA}]\cdot V_a=0.1\cdot V_a$
Base: $n_b = [\ce{HA}]\cdot V_b=0.1\cdot V_b$
and I need to calculate the amount of acid and base in $15\ \text{ml}$ of the buffer, which I worked out to equal
$V_a=9.7\ \text{ml}$
$V_b=5.3\ \text{ml}$
How would I start this question? Wh... |
Quick run down, I was given ph OF BUFFER 4.5 AND THEN pKa of acid 4.79
I then had to work out volume of acid and volume of base using pH=pKa+log10([a^-1]/[HA])
using that I calculated the volumes of acid and base required to make 15ml of the buffer CH3COOH,CH3COONa
Va=9.7ml and Vb=5.3 (BOTH ACID/BASE used to ma... |
![enter image description here][1]
The answer is D.
I understand that when more H+ ions are added, the reaction shifts in reverse.
So I've understood that this is known as having the equilibrium shift to the left, toward the reactants.
What confuses me is why Kc doesn't change. If the equilibrium shifts to ... |
Le Chatelier's Principle: How can the equilibrium shift, while Kc remains constant? |
I keep trying to figure out how current is conducted through an electrolyte but all I can find are BS half answers. They say the ions conduct, but the specifics are poorly explained or absent. I understand that if you, for example, put sodium chloride in water it will disassociate into positive sodium ions and negative... |
To add to Nick's great answer, I believe you are confusing $K_c$, the equilibrium constant, with $Q_c$, the reaction quotient.
The reaction quotient is defined as the ratio of the product of the concentrations of the products to the product of the concentrations of the reactants, under any conditions or relative amo... |
A quick search in my university's library for `Life cycle polymer` brings me two reputable looking books:
1. [*Green composites: Polymer composites and the environment*][1]
2. [*Fundamentals of Materials for Energy and Environmental Sustainability*][2]
A [Google Scholar search][3] for `life cycle analysis of pl... |
What Could Formations of Linkage Isomers of [Co(NH3)NO2]^2+ be like ? |
Does a rotary evaporator need a draft chamber and a vacuum pump? |
I think you are taking too dogmatic a position overall.
1) Vacuum also increases the rate of evaporation, without boiling. This is just practical.
2) Your claim that your system is "completely closed" is over confident. What if you are wrong and you have a leak? Now you are free to dismiss this, but this is the... |
We know that the Greeks were the first scientists (or better, philosophers) to introduce the idea that matter is made up of little “chunks”, and they named these chunks “atoms”. This idea that matter comes in discrete small pieces was termed wrong and right over centuries when John Dalton, in the 19th century, construc... |
We know that the Greeks were the first scientists (or better, philosophers) to introduce the idea that matter is made up of little “chunks”, and they named these chunks “atoms”. This idea that matter comes in discrete small pieces was termed wrong and right over centuries when John Dalton, in the 19th century, construc... |
In polysachharides like sucrose or any other disachhaharides , how is it that we assign whether the glycosidic bond is alpha/beta ?
For example the images here: http://forums.studentdoctor.net/showthread.php?t=898328 (kindly refer to the images of the original question,both of them)
How does one decide which glyc... |
In [Price & Dwek][1], I find a small section discussing entropy of activation for three examples
$$
1: \ce{Ce^{4+}} + \ce{EDTA}^{4-} \rightarrow (\ce{CeEDTA})\\
2, \text{S}_N\text{1 reaction}: \ce{AB} \rightarrow [A^+...B^-]^\ddagger\\
3, \text{S}_N\text{2 reaction}: \ce{AB} + \ce{C^-} \rightarrow [\ce{C...A...B}... |
YOU DONT DO ANY WORKOUT ANYTHING FOR ME HERE I , JUST GIVING AN EXAMPLE SO YOU CAN EXPLAIN SOMETHING TOO ME :)
CIF3(g) <=> CIF(g) + F2(g), Kc=8.77.10^-14 at 279K (standard state =1molL^-1) what is [CIF] as equilibrium if initially [CIF3]=2.S0molL^-1 and [F2]= 1.00mol/L
so
Kc= ([CIF][F2])/[CIF3] = [x. (1+x)]/(2.5... |
You don't need to work out anything for me. I am just giving an example so you can explain something to me.
For example:
$$\ce{ClF3(g) <=> ClF(g) + F2(g)}\\ \ \ K_c=8.77\times10^{-14} \ \ @\ 279\ \text{K}$$
What is $[\ce{ClF}]$ at equilibrium if initially $[\ce{ClF3}]=2.50 \ M$ and $[\ce{F2}]= 1.00\ M$?
$$K... |
What does it mean for a reaction to favor the reactants/products? |
Why does Butane burn blue? From my (very) basic understanding of chemistry, carbon and hydrogen do not burn blue, their radiation spectra are different-so why should the combination burn blue?
Please elaborate as much as possible, about bonds, orbitals, electrons, and the like! |
If a reaction is exothermic it means that the energy state of the products is lower than that of the reactants so this will be the state that 'nature' will naturally strive for. Often you see that stability of molecules is argued in this way (e.g. in one of the answers [here][1]), saying that the higher the exothermici... |
If a reaction is exothermic it means that the energy state of the products is lower than that of the reactants so this will be the state that 'nature' will naturally strive for. Often you see that stability of molecules is argued in this way (e.g. in one of the answers [here][1]), saying that the higher the exothermici... |
I missed my lesson on periodicity so had to teach myself, and have always forgotten to ask my teacher to explain to me why these trends are seen, which, unfortunately, the textbooks don't.
**Density**: the density of an element tends to increase across a period up to group 3, and then starts to decrease and become v... |
Why is periodicity seen in these certain properties? |
Can I synthesize salicylic from salycylaldehyde? |
Can I synthesize salicylic acid from salycylaldehyde? |
The title more or less contains my question - why does the Förster resonance energy transfer (FRET) (photon?)-based energy transfer mechanism, which folks sometimes use as a spectroscopic ruler to measure the inter-particle spacing between dye pairs, exhibit $\frac{1}{r^6}$ scaling for energy transfer efficiency? Sinc... |
Why does the Förster resonance energy transfer exhibit $\frac{1}{r^6}$ scaling? |
How does the balanced reaction look for these compounds? I found that phosphoric acid instead of hydrogen phosphate creates a much easier problem, but the teacher said hydrogen phosphate and I can't seem to balance it.
calcium carbonate react with hydrogen phosphate to produce calcium phosphate, carbon dioxide and... |
What Is This Colorless Ferric Solution? |
Proving something is a rather nebulous task when there is no judge or jury and consensus is arrived at gradually over a century rather than instantaneously. Many scientists would consider the atom "proved" decades apart.
Avogadro was the first to distinguish atoms from molecules, which alleviated much confusion reg... |
Ferric Acetate (II) and (III) are "[mordants][1]," which intensify wood staining in direct proportion to the tannin concentration in the wood. Some wood stainers add tea to increase the tannin content and thereby make the stain darker. How does Ferric Acetate act as a mordant in this case of [Ebonizing][2] wood?
... |
How Does The Mordant, Ferric Acetate, Interact With Tannins When Ebonizing Wood? |
In [Goodman & Gilman's The Pharmacological Basis of Therapeutics, 12e][1] R,S-citalopram is referred to. The problem is that from what I am aware of citalopram only has one stereocentre, and hence I am forced to ask were the author having a stroke when they added the comma and really meant the racemic mixture of R and ... |
In Goodman and Gilman what does R,S-citalopram refer to? |
In [Goodman & Gilman's The Pharmacological Basis of Therapeutics, 12e][1] R,S-citalopram is referred to. The problem is that from what I am aware of citalopram only has one stereocentre, and hence I am forced to ask were the author having a stroke when they added the comma and really meant the racemic mixture of R and ... |
My guess at why diesel produces more carbon monoxide is that more heat is required for combustion of diesel fuel, so there is therefore less incomplete combustion, so rather than carbon monoxide being formed and released, the ability to completely combust means that carbon dioxide is often formed instead. Correct me if... |
How can diesel fuel produce less carbon monoxide but more carbon particulates? |
Let's say I have a large quantity of rust and want to extract the oxygen from it in a way that allows me to collect the oxygen in a container.
What chemical process can I use to do this and what equipment does it require?
It's preferable if the process is doable at home so I can demonstrate the process but it's n... |
The binding of proteins to an ITO surface can be prevented by coating it with PEG groups (polyethylene glycol). PEG-silane is used to create the coating.
can somebody help with:
*Why does PEG silane bind to ITO (indiumtinoxide)? and how? (which bond etc.)
*Why does PEG repel proteins?
*Are there better co... |
By chance we received for free some graphene sheets at our University. I would like to prepare some very easy to do experiments for the chemistry students that show the awesome properties of graphene, and which could be carried out with very simple lab equipment or even home experiments, any ideas or references?
|
Did where come the acac on Cr(acac)3 synthesis by CrCl3 reagent? |
By chance we received for free some monolayer graphene sheets (20 cm x 20 cm) and mixed coper-graphene wires at our University. I would like to prepare some very easy to do experiments for the chemistry students that show the awesome properties of graphene, and which could be carried out with very simple lab equipment ... |
When Did Atom Theory Become Indisputible? |
We know that the Greeks were the first scientists (or better, philosophers) to introduce the idea that matter is made up of little “chunks”, and they named these chunks “atoms”. This idea that matter comes in discrete small pieces was termed wrong and right over centuries when John Dalton, in the 19th century, construc... |
When did the atom Theory Become indisputable? |
Where did the acac come from in Cr(acac)3 synthesis by CrCl3 reagent? |
My question is if any energy is required to form bonds, for instance when there is a phase change?
If I am correct, energy might be required in the beginning, to make the reaction start and then release a bigger amount of energy than it was putted in. However, in terms of molecular behaviour in a phase change, I thi... |
I am a confused (and somewhat anal retentive) non-chemist who is trying to understand what pH is. I have come to understand it is a measure of acidity, but I have not yet figured out what that means to a precision that I find satisfying.
Please excuse me if these are dumb questions, but they will help me understand... |
I'd like know if this is right. The reaction between $NaCl$ and $H_2SO_4$ should yield $HCl$ and sodium sulfate. This is a double substitution, true? No oxidation took place here. The thing is, when I tried the reaction in the lab, the resulting solution (gas bubbled into water) seemed to be sulfuric acid. Simply enoug... |
Did you not carry out some research?
Well, you can find information about it in [Wikipedia](https://en.wikipedia.org/wiki/PH#pH), or even dictionaries like [Merriam-Webster](http://www.merriam-webster.com/dictionary/ph) or [Dictionary Online](http://dictionary.reference.com/browse/Ph).
You will see that pH is cal... |
Excellent thought. On the one hand, you have learned that the partial pressure of water (or any other volatile liquid) is a function of the temperature alone, but on the other, you are finding a non-constant relationship with your calculation. Let's dig into the former approach first. We talk about [the Clausius-Clapey... |
Excellent thought. On the one hand, you have learned that the partial pressure of water (or any other volatile liquid) is a function of the temperature alone, but on the other, you are finding a non-constant relationship with your calculation.
The short answer:
The water pressure stays constant because as the... |
Excellent thought. On the one hand, you have learned that the partial pressure of water (or any other volatile liquid) is a function of the temperature alone, but on the other, you are finding a non-constant relationship with your calculation.
**The short answer**
The water pressure stays constant because as th... |
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