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Which Chemical Database Software Are Available? |
How can one calculate the pH of a solution? |
Why do big thermoplastics (like Polytetrafluoroethylene) behave like thermosets? I know for sure it has to do with the van der Waals force and the fact that the molecules are huge, but why? Why does a big molecule break down before the van der Waals forces break? |
Why do big thermoplastics (like Polytetrafluoroethylene) behave like thermosets? |
What is the reaction between Magnesium chloride and Sodium bicarbonate? |
I think your question implicates another question (which is also mentioned in some comments here), namely: Why are all energy eigenvalues of states with a different **angular momentum quantum number** $\ell$ but with the same **principal quantum number** $n$ (e.g. $3s$, $3p$, $3d$) degenerate in the hydrogen atom but n... |
What is the best method for predicting the water solubility (and in other solvents) of a compound given its molecular structure? |
What makes electrolysis or electroplating take so long ? What stage takes longer when ions are attracted to electrodes or when they gain or lose electrons at electrode.
And if we are talking about an electrolyte composed of positive ions and electrons , which is faster, electrons entering the circuit at positive elect... |
Why does electrolysis take so much time? |
I have a chemistry homework problem that asks whether $Br_2$ or $O_2$ is more soluble in water in room temperature. However, I can't seem to find a way to figure it out, short of looking it up.
Is there a guiding rule for such figures, such as relating to molar mass? |
The two broad a halogen can leave a haloalkane are [nulceophilic substitution][1] and elimination reactions.
I was told that [elimination reactions][2] (that form a double bond as a $H^+$ is another leaving group here) do not occur when the haloalkane is dissolved in water; here nucleophilic substitution (anion repl... |
Why does nucleophilic substitution favour being in an aqueous solution? |
I'm sure most of us have heard that saturated fats are solid at room temperature, and unsaturated fats are liquid at room temperature. I'm wondering how this relates to their chemical structure -- saturated fats contain only single bonds between carbons, yet to qualify as an unsaturated fat a C=C double bond must exist... |
Saturated vs Unsaturated Fats -- Structure in Relation to Room Temperature State? |
I'm not detecting ammonia in my samples while using a NOESY pulse program for a 1H-NMR experiment.
So, the question is: Can ammonia be detected by a 1D-1H-NOESY experiment?
Thanks! |
Can ammonia be detected by a 1D-1H-NOESY experiment? |
I'm not detecting ammonia in my samples while using a NOESY pulse program for a 1H-NMR experiment.
Is it possible for ammonia to be detected by a 1D-1H-NOESY experiment?
|
Why isn't water acidic? |
First off, NOESY is a tool that gives information more useful for structure determination and confirmation (as Mad Scientist has explained). A simple and quick 1H NMR experiment should be enough to quantify your compounds assuming you have sufficient peak resolution (often a problem with multiple compound quantificatio... |
How is the time for a test tube in a centrifuge determined? |
Is this enthalpy change question possible? |
I came across some hairy math that's used for analytical centrifugation, mostly for things like determining the sedimentation rate for liquids.
However, what I don't understand is how someone determines how long a test tube should be inside a centrifuge? Is it based off of others experimental data or is there a fix... |
When we run a current through water (pure or not), O_2 forms at the anode while H_2 forms at the cathode. If I understand correctly, as water is already slightly ionized, H's snap together (and so do O's) during the electron exchange. Is it possible to apply enough heat or enough pressure to water to prevent H's and O'... |
Is it possible to form bubbles of ionized hydrogen and ionized oxygen under the right pressure/temperature conditions during electrolysis of water? |
When we run a current through water (pure or not), $\ce{O_2}$ forms at the anode while $\ce{H_2}$ forms at the cathode. If I understand correctly, as water is already slightly ionized, $\ce{H}$'s snap together (and so do $\ce{O}$'s) during the electron exchange. Is it possible to apply enough heat or enough pressure to... |
I am trying to run a molecular dynamics simulation with AMBER forcefield. However, it's the first time I use is, and while I know the form of the various intra- and intermolecular energy terms, some details are not clear to me. So, for the AMBER forcefield:
- **What pairs are excluded in the summation of intramolecu... |
For example, take $O_2$.
The oxidation state of oxygen is -2, yet once its in a molecule its oxidation state becomes zero?
How is this so? |
Why do single elements in a molecule have an oxidation state of zero? |
http://i.imgur.com/wRojr3T.jpg - New user, can't insert the image :-)
Above is a $^1H$ Nuclear Magnetic Resonance (NMR) spectrum for benzyl alcohol. The hydrogen in the alcohol group gives rise to a unique signal. The two hydrogens in CH2 give rise to a unique signal with around twice the signal area. What I don't u... |
1H-NMR problem. Why are these hydrogen equivalent? |
![http://i.imgur.com/wRojr3T.jpg][1]
Above is a $^1H$ Nuclear Magnetic Resonance (NMR) spectrum for benzyl alcohol. The hydrogen in the alcohol group gives rise to a unique signal. The two hydrogens in CH2 give rise to a unique signal with around twice the signal area. What I don't understand is why all hydrogens in... |
I have posted two reactions below. The top reaction is well known and occurs readily and near quantitatively (e.g. in protein modification), while the bottom reaction to my knowledge does not exist in the literature, but would be valuable to me. I would like to ask the experienced organic chemists out there if you thin... |
A Chemistry homework question:
Which of the following statements best characterizes the difference between the titration of a strong acid with a strong base and that of the titration of a weak acid with a strong base?
a. Both the strong acid and the strong base are completely dissociated in solution whereas the w... |
Chemistry Homework Help, Acid-Base Titrations? |
A Chemistry homework question:
Which of the following statements best characterizes the difference between the titration of a strong acid with a strong base and that of the titration of a weak acid with a strong base?
a. Both the strong acid and the strong base are completely dissociated in solution whereas the w... |
![enter image description here][1]
Above is a $^1H$ Nuclear Magnetic Resonance (NMR) spectrum for benzyl alcohol. The hydrogen in the alcohol group gives rise to a unique signal. The two hydrogens in CH2 give rise to a unique signal with around twice the signal area. What I don't understand is why all hydrogens in t... |
We made a solution of Tetrakis Copper(I) hexafluorophosphate and the usual color is yellowish. As it oxidizes to Cu(II), it should turn blue.
However, our current mixture has an off color that is pink. Looking up alternative copper colors, there will be copper rose. What would cause that color? |
What causes Copper Rose? |
How to determine the oxidation number of nitrogen in $KCN$ ?
|
KCN is a ionic compound consisting of $\ce{K+}$ and $\ce{CN-}$. You can know that the cyanide ion will have a negative charge, because potassium always has a positive. Also the elements in the cyanide ion are more electronegative - that means they will have the negative oxidation number.
So we know that since potass... |
How can one determine the oxidation number of nitrogen in $\ce{KCN}$ ?
|
A Chemistry homework question:
>Which of the following statements best characterizes the difference between the titration of a strong acid with a strong base and that of the titration of a weak acid with a strong base?
>
> A) Both the strong acid and the strong base are completely dissociated in solution whereas t... |
I'm having serious problems in the electronic configuration of Iron dioxide $\ce{Fe(OH)2}$ because all I could come up with was Fe double bonded with each Oxygen and single bonded with each hydrogen, everything seems good except for the iron that's bonded with 5 atoms (which I think is weird). Could someone you give me... |
KCN is a ionic compound consisting of $\ce{K+}$ and $\ce{CN-}$. You can know that the cyanide ion will have a negative charge, because potassium always has a positive. Also the elements in the cyanide ion are more electronegative - that means they will have the negative oxidation number.
So we know that since potass... |
I'm having serious problems in the electron configuration of iron dioxide $\ce{Fe(OH)2}$ because all I could come up with was $\ce{Fe}$ double bonded with each oxygen and single bonded with each hydrogen.
Everything seems good except for the iron that's bonded with 5 atoms (which I think is weird). Could someone yo... |
How can one determine the oxidation number of nitrogen in KCN?
|
KCN is a ionic compound consisting of $\ce{K+}$ and $\ce{CN-}$. You can know that the cyanide ion will have a negative charge, because a potassium ion always has a positive. Also the elements in the cyanide ion are more electronegative - that means they will have the negative oxidation number.
So we know that since ... |
When you study the electronegativity of the elements, the general trend is that it rises with increasing group number, and decreasing period.
Supposedly this is because the attractive forces of the nucleus increase quicker than the shielding effect of the electrons.
1. Is this shielding effect simply a repellant ... |
Why does attractive forces of nucleus increase more than shielding across groups? |
When you study the electronegativity of the elements, the general trend is that it rises with increasing group number, and decreasing period.
Supposedly this is because the attractive forces of the nucleus increase quicker than the shielding effect of the electrons.
1. Is this shielding effect simply a repellant ... |
How can you estimate how much of a substance with a known partition coefficient and other physical/chemical data regarding the substance will dissolve in a given lipid? In particular I would like to know the answer to this question in the context of the blood-brain barrier (BBB). |
How can you estimate how much of a substance will dissolve in a given lipid? |
How does a substance with an endothermic heat of reaction dissolve? |
Why does a substance with an endothermic heat of solution dissolve? |
Dissolution happens in three steps.
Solute-solute attractions must be broken (consumes energy, endotherm), solvent-solvent attractions must be broken (also endotherm), and finally solute-solvent attractions form. This results in a lower energy state and is exotherm.
Dissolution will be endotherm if it takes more ... |
Dissolution happens in three steps.
Solute-solute attractions must be broken (consumes energy, endotherm), solvent-solvent attractions must be broken (also endotherm), and finally solute-solvent attractions form. This results in a lower energy state and is exotherm.
Dissolution will be endotherm if it takes more ... |
How does a substance with an endothermic heat of solution dissolve? |
I used my water kettle (metal ones, not the plastic ones) to boil my water. Usually, if I did not consume all the water in the kettle and the water was cold, I usually topup extra water to the kettle and turn it on to boil.
So, after many weeks of boiling in this way, I notice that there are white powder outside the... |
**How would I synthesise LY-293,284?**
![enter image description here][1]
Figure 1: LY-293,284
--------------------
I have satisfied the conditions at the page http://meta.chemistry.stackexchange.com/questions/205/should-we-allow-synthesis-questions-subject-to-the-six-constraints-listed-below so please don't ju... |
How would you Synthesise LY-293,284? |
**How would I synthesise LY-293,284?**
![enter image description here][1]
Figure 1: LY-293,284
--------------------
I have satisfied the conditions at the page http://meta.chemistry.stackexchange.com/questions/205/should-we-allow-synthesis-questions-subject-to-the-six-constraints-listed-below so please don't ju... |
**How would I synthesise LY-293,284?**
![enter image description here][1]
Figure 1: LY-293,284
--------------------
I have satisfied the conditions at the page http://meta.chemistry.stackexchange.com/questions/205/should-we-allow-synthesis-questions-subject-to-the-six-constraints-listed-below so please don't ju... |
**How would I synthesise LY-293,284?**
![enter image description here][1]
Figure 1: LY-293,284
--------------------
I have satisfied the conditions at the page http://meta.chemistry.stackexchange.com/questions/205/should-we-allow-synthesis-questions-subject-to-the-six-constraints-listed-below so please don't ju... |
**How would I synthesise LY-293,284?**
![enter image description here][1]
Figure 1: LY-293,284
--------------------
I have satisfied the conditions at the page http://meta.chemistry.stackexchange.com/questions/205/should-we-allow-synthesis-questions-subject-to-the-six-constraints-listed-below so please don't ju... |
**How would I synthesise LY-293,284?**
![enter image description here][1]
Figure 1: LY-293,284
--------------------
I have satisfied the conditions at the page http://meta.chemistry.stackexchange.com/questions/205/should-we-allow-synthesis-questions-subject-to-the-six-constraints-listed-below so please don't ju... |
There was some spirited debate between the members of my chemistry lab today about the theoretical consequences of ingesting a large amount of the detergent Triton X-100 at a 100% concentration. The [MSDS][1] provided by Sigma Aldrich indicates that it is "harmful if swallowed," with a LD50 of 1800mg/kg in rats, but do... |
Impact of detergent on internal living tissue? |
My friend split a "level 4 carcinogen" on their lap. What is it and how dangerous is it?
They had washed if off after. |
What is a level 4 carcinogen? |
A very long time ago I performed an experiment in my kitchen, part of which was to remove all water from a solution. Unfortunately I don't remember what was in it, but the point is that as the solution got more concentrated, it gradually stopped boiling, and would instead remain completely still for seconds, until a hu... |
Why do some solutions eventually stop boiling and start "popping" as they get more concentrated? |
My friend spilt a "level 4 carcinogen" on their lap. What is it and how dangerous is it?
They had washed if off after. |
When talking about gaseous fuel / oxidizer mixture what does one mean by oxidizer if there is no oxygen involved?
Is it correct to think of oxidizer as the more electronegative specie, because it is pulling the electron? Or is this definition only valid for solutions?
The Wikipedia [article](http://en.wikipedia.org... |
Where did the INN name of Fentanyl come from? Fentanyl is a potent anilidopiperidine opioid. I know that the INN name of paracetamol came from its chemical name para-acetylaminophenol (**par-acet-am-ol**). Is there a meaningful origin of the INN name of fentanyl?
<br>
<br>
<br>
![enter image description here][1]
... |
Where did the INN name of Fentanyl come from? |
How long chain alcohols(not thiols) can be functionalised in the surface of Silver or Gold Nanoparticle. I have read in an article Poly vinyl alchol is used as a capping agent for silver nanoparticle synthesis but what is the mechanism for that? What type of bonds forms between nanoparticle and the long chain alchol(co... |
How can long chain alcohols(not thiols) be functionalised on the surface of silver or gold nanoparticles?
I have read in an article that Polyvinyl alcohol is used as a capping agent for silver nanoparticle synthesis, but what is the mechanism for that?
What type of bonds form between nanoparticle and the long c... |
My teacher gave me question:
What is the possible product of these reaction? Then, what is the mechanism of those reaction (elimination ($E1$ or $E2$) or subtitution ($S_N1$ or $S_N2$))? Explain as much detail as possible.
$\ce {CH3Cl + OH- ->}$ $?$
<Br>
$\ce {(CH3)3CCl + OH- ->}$ $?$
|
My teacher gave me the following question:
> What are the possible products of these reactions? Then, what is the mechanism of those reaction (elimination ($E1$ or $E2$) or subtitution ($S_N1$ or $S_N2$))? Explain in as much detail as possible.
>$$\ce {CH3Cl + OH- ->} ?$$
>$$\ce {(CH3)3CCl + OH- ->}?$$
|
My teacher gave me the following question:
> What are the possible products of these reactions? Then, what is the mechanism of those reaction (elimination ($E1$ or $E2$) or subtitution ($S_N1$ or $S_N2$))? Explain in as much detail as possible.
>$$\ce {CH3Cl + OH- ->} ?$$
>$$\ce {(CH3)3CCl + OH- ->}?$$
<Br>... |
My teacher gave me the following question:
> What are the possible products of these reactions? Then, what is the mechanism of those reaction (elimination ($E1$ or $E2$) or subtitution ($S_N1$ or $S_N2$))? Explain in as much detail as possible.
>$$\ce {CH3Cl + OH- ->} ?$$
>$$\ce {(CH3)3CCl + OH- ->}?$$
<Br>... |
My guess: the name may be based on two of the immediate precursors to the drug, N-Phenethyl-4-piperidone (FENT, from Phen + ethyl?) and aniline (ANYL):
![enter image description here][1]
Definitely not as straight-forward as your para-acetylaminophenol example.
[1]: https://i.stack.imgur.com/rwCTj.png |
Ammonia has a heat of formation of -46 kJ/mol (which means that it's formation from the elements releases heat). When mixed with iodine at room temperature, it makes nitrogen triodide (heat of formation +146 complexed with ammonia, +287 pure). With the slightest tough it decomposes eplosivly back into nitrogen and iodi... |
I'm not sure what your question is. The reaction from NI<sub>3</sub> is largely exothermic (Wikipedia gives –290 kJ/mol as the reaction enthalpy), which is consistent with its explosiveness. The reaction from NI<sub>3</sub> · NH<sub>3</sub> is also exothermic: you quote the heat of formation of the NI<sub>3</sub> · NH<... |
I'm trying to do homework and I have the answers to the problems but I can't read the explanation because it's illegible and I can't find how it's done in my notes.
Here's the simplest example:
C + O_2 --> CO_2
It looks like the answer is 44/12 but I don't understand where the 12 comes from at all. How is a qu... |
I'm trying to do homework and I have the answers to the problems but I can't read the explanation because it's illegible and I can't find how it's done in my notes.
Here's the simplest example:
$$\ce{ C + O_2 \to CO_2}$$
It looks like the answer is 44/12 but I don't understand where the 12 comes from at all. H... |
You have 1 mol $\ce{C}$ reacting with 1 mol $\ce{O_2}$ to give 1 mol of $\ce{CO_2}$
What you need now is something to relate weight and mol. This is called molar mass, notated with the letter M, and has the unit g/mol. You'd just look that up on the internet, but it's calculated from the weight of the atoms in each ... |
Ammonia has a heat of formation of -46 kJ/mol (which means that it's formation from the elements releases heat). When mixed with iodine at room temperature, it makes nitrogen triodide (heat of formation +146 complexed with ammonia, +287 pure). With the slightest tough it decomposes eplosivly back into nitrogen and iodi... |
I just don't understand how to do these and would really appreciate your help.
1) Ammonium Dichromate decomposes in a reaction when heated. Calculate the heat transferred for the decomposition of 53.0 g of Ammonium Dichromate according to
(NH4)2Cr2O7(s) ----> Cr2O3(s) + N2(g) + 4H2O(g) ΔH° = -315 kj
Do I convert ... |
Ammonia has a heat of formation of -46 kJ/mol (which means that it's formation from the elements releases heat). When mixed with iodine at room temperature, it makes nitrogen triodide (heat of formation +146 complexed with ammonia, +287 pure). With the slightest touch it decomposes explosively back into nitrogen and io... |
I just don't understand how to do these and would really appreciate your help.
1) Ammonium dichromate decomposes in a reaction when heated. Calculate the heat transferred for the decomposition of 53.0 g of ammonium dichromate according to
$\ce{(NH4)2Cr2O7(s) -> Cr2O3(s) + N2(g) + 4H2O(g)}$ ΔH° = -315 kJ
Do I conv... |
Most materials become more dense as they cool, but ice floats in water, meaning that it's less dense. Why is this? |
Why do metals want to gain electrons, as opposed to maintaining electric neutrality? |
Why do metals tend to lose electrons, as opposed to maintaining electric neutrality? |
**Oxidation:** losing electron(s), **Oxidizer / oxidizing agent:** a chemical that can oxidize another reagent. **Reduction:** gaining electron(s) - think of it as reduction of charge! **Reducing agent:** A chemical that can reduce another reagent.
And oxidation can never occur without a reduction, meaning if you us... |
Ammonia has a heat of formation of $-46 \:\mathrm{kJ/mol}$ (which means that it's formation from the elements releases heat). When mixed with iodine at room temperature, it makes nitrogen triodide (heat of formation +146 complexed with ammonia, +287 pure). With the slightest touch it decomposes explosively back into ni... |
What is an oxideser? |
What is an oxidizer? |
Brian's answer is very good and thorough, but there is one rather important empirical fact you need to consider with reduction potentials. While the difference in $\ce{E_0}$ values can tell you if a reaction *can* occur, it cannot tell you if a reaction *will* occur. There are other factors, like reaction rate and ac... |
**Oxidation:** losing electron(s), **Oxidizer / oxidizing agent:** a chemical that can oxidize another reagent. **Reduction:** gaining electron(s) - think of it as reduction of charge! **Reducing agent:** A chemical that can reduce another reagent.
And oxidation can never occur without a reduction, meaning if you us... |
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