instruction stringlengths 15 21.8k |
|---|
In enzyme kinetics, there is a similar situation, where the symbol $E_t$ is used to indicate the "total enzyme concentration".
In other words, there can be free enzyme with concentration [E], substrate bound enzyme with concentration [ES], and inhibitor bound enzyme [EI], but for the total concentration of all for... |
According to [these lecture notes from Gonzaga University](http://guweb2.gonzaga.edu/faculty/cronk/CHEM440pub/L26-index.cfm?L26resource=thioesters):
> The question arises over why thioesters occupy a prominent place in metabolism while oxygen esters play a relatively minor role. One answer is thermodynamic. The sulf... |
If 2.4 moles of gas fill a volume of 175 mL, what volume, in mL, will 5.4 additional moles of gas fill?
This was a quiz question which I got wrong the first attempt, and I think I got it right this time however I would like some confirmation that it is/is not. The unnamed gas is assumed to be ideal.
2.4M/175mL=7.8M... |
Also, why can some elements such as $\ce{Fe}$ have different ionic forms such as $\ce{Fe^{2+}}$ and $\ce{Fe^{3+}}$? What determines each form? |
I'm an AP Chemistry student, and we're doing the Decomposition of $\ce{H2O2}$ lab, in which we decompose $\ce{H2O2}$ with $\ce{KI}$ as a catalyst. I've gotten this data so far:
+-------+-------------+----------------+-----------+--------------+-------------+--------------+--------------------+-------------------... |
Why does ClO₄⁻ only have 3 double bonds? |
Molarity (M) is defined as moles of solute per liter of solution while Normality (N) is defined as moles of reacting units per liter of solution. Most texts use sulfuric acid as an example to demonstrate the difference: a 1 M solution of sulfuric acid is 2 N because each mole of sulfuric acid gives two moles of H+ (th... |
Molarity (M) is defined as moles of solute per liter of solution while Normality (N) is defined as moles of reacting units per liter of solution. Most texts use sulfuric acid as an example to demonstrate the difference: a 1 M solution of sulfuric acid is 2 N because each mole of sulfuric acid gives two moles of $\ce{H... |
Who labels concentrated sulfuric acid as 18N? 36N sound right to me and Sigma-Aldrich:
>Concentration: The commercial reagent contains 93-98% H2SO4, the balance being water. Its effective concentration is 18 M (36N).
https://www.sigmaaldrich.com/content/dam/sigma-aldrich/docs/Sigma-Aldrich/Product_Information_Sh... |
Molarity (M) is defined as moles of solute per liter of solution while Normality (N) is defined as moles of reacting units per liter of solution. Most texts use sulfuric acid as an example to demonstrate the difference: a 1 M solution of sulfuric acid is 2 N because each mole of sulfuric acid gives two moles of $\ce{H... |
Who labels concentrated sulfuric acid as 18N? 36N sounds right to me and Sigma-Aldrich:
>Concentration: The commercial reagent contains 93-98% H2SO4, the balance being water. Its effective concentration is 18 M (36N).
https://www.sigmaaldrich.com/content/dam/sigma-aldrich/docs/Sigma-Aldrich/Product_Information_S... |
At low concentration, conductivity is proportional to concentration (a linear relationship).
Each ion will have its own unique mobility, as discovered by Kohlrausch. H+ has the highest mobility. As you can see in your graph the acids have higher conductivities than the salts. OH- is also highly mobile.
As con... |
You'd need to have some sort of ligand dictionary. For many PDB ligands, this exists, and you can look up the atom naming.
For example, the [PDB ligand expo](http://ligand-expo.rcsb.org/) allow you to search for ligands by 3-letter code (e.g., [HEM](http://ligand-expo.rcsb.org/pyapps/ldHandler.py?formid=cc-index-sea... |
Why does magnesium have the lowest melting point of all earth alkali metals? |
Why does magnesium have the lowest melting point of all earth alkalis? |
Is there a material which can be applied to a surface that will block liquids but is dissolved by blood? |
Is there something which will block liquids but is dissolved by blood? |
Suppose I had an acid HA, and it reaches equilibrium in water. Then I remove the hydronium ions. I don't know how I would do this, maybe adding some hydroxide ions. My question is can I do this and will I be able to eventually create a 50/50 mixture of acid and conjugate base? Is this a very good buffer.
warning, t... |
What happens if I have an Acid/Base equillibrium and remove hydronium ions until there is 50/50 of Acid and conjugated base? |
Why is it difficult to detect [dopamine](http://www.hmdb.ca/spectra/nmr_one_d/1070) using <sup>1</sup>H Magnetic Resonance Spectroscopy (MRS) in the brain (_in vivo_)?
|
Is there a material which can be applied to a surface that will block liquids but is dissolved by blood?
The idea is to use the liquid to close a circuit, but only if blood is present, so I'm wondering if a barrier that would be dissolved by blood can prevent other liquids from reaching the circuit. |
There are numerous approximations made when pH calculations like these are made.
In a problem like this the approximations that would usually be made are
1. pH = -log[H+] (as opposed to pH being -log (H+ activity) which is the true definition).
2. NaOH is an infinitely strong base, with NaOH completely di... |
There are numerous approximations made when pH calculations like these are made.
In a problem like this the approximations that would usually be made are
1. pH = -log[H+] (as opposed to pH being -log (H+ activity) which is the true definition).
2. NaOH is an infinitely strong base, with NaOH completely di... |
Why is it difficult to detect [dopamine](http://www.hmdb.ca/spectra/nmr_one_d/1070) using $\ce{^1H}$ Magnetic Resonance Spectroscopy (MRS) in the brain (_in vivo_)?
|
Like $\ce{Fe}$, it can be $\ce{Fe^{2+}}$ or $\ce{Fe^{3+}}$, same with $\ce{Ni}$ and $\ce{Co}$, what determines whether the ionic compound will be $\ce{Fe^{2+}}$ or $\ce{Fe^{3+}}$? |
Would molecules like $\ce{C2, H2}$, etc., be considered 1 mole of diatomic [element] or 2 moles of [element]? |
Would 2 C₂ be 2 moles of diatomic carbon, or 4 moles of carbon? |
Who labels concentrated sulfuric acid as 18N? 36N sounds right to me and Sigma-Aldrich:
>Concentration: The commercial reagent contains 93-98% H2SO4, the balance being water. Its effective concentration is 18 M (36N).
https://www.sigmaaldrich.com/content/dam/sigma-aldrich/docs/Sigma-Aldrich/Product_Information_S... |
Suppose I had an acid HA, and it reaches equilibrium in water. Then I remove the hydronium ions. I don't know how I would do this, maybe adding some hydroxide ions. My question is can I do this and will I be able to eventually create a 50/50 mixture of acid and conjugate base? Is this a very good buffer? |
What happens if I have an acid/base equillibrium and remove hydronium ions until there is 50/50 of acid and conjugate base? |
Given a 19kg Liquid Petroleum Gas (LPG) cylinder, with this specification:
- LPG inside the cylinder weighs `19kg`.
- The internal volume of the cylinder is `44.5 litres`.
- The LPG is a mixture of `propane gas (60%)` and `butane (40%)`.
I would like to calculate the **volume** of LPG contained in the cylin... |
How much gas is inside a pressurised gas cylinder? |
You can't just remove hydronium ions because the solution needs to remain electrically neutral.
You can't just add hydroxide ions, but you could add sodium hydroxide until the HA/A- ratio was 50/50.
>Is this a very good buffer?
It is the optimum ratio of HA and A- for buffering. |
Would it be possible to create a (non-toxic) alcoholic drink that, when zapped with a 0.5mW laser pointer, changes color?
This would be mainly for the visual effects so it should not require aiming the laser at the drink for more than a few seconds. The reason for choosing a 0.5mW laser is to minimize the need for e... |
Would it be possible to create a (non-toxic) alcoholic drink that, when zapped with laser, changes color? |
Is there a material which can be applied to a surface that will block liquids but is dissolved by blood?
The idea is to use the liquid to close a circuit, but only if blood is present. I'm wondering if a barrier that would react to the chemical components of blood by dissolving can prevent other liquids from reachin... |
Is 2-bromobutane chiral? |
Would it be possible to create a (non-toxic) alcoholic drink that, when zapped with a 0.5mW laser pointer, changes color?
This would be mainly for the visual effects (bartender show) so it should not require aiming the laser at the drink for more than a few seconds. The reason for choosing a 0.5mW laser is to minimi... |
Is there a material which can be applied to a surface that will block liquids but is dissolved by blood?
The idea is to use the liquid to close a circuit, but only if blood is present.
I'm wondering if there is something I can coat on the circuit to act as a barrier preventing other liquids from reaching the circ... |
Identifying rearrangement reaction? |
I see a couple of problems here:
### Beam diameter vs volume of the beverage
The volume of the sample that is actually hit by a narrow laser beam is very small, as compared to the total volume of the sample (= the drink). As a consequence, only a very small amount of the dye in drink will undergo a transformation... |
During the creation of $\ce{Al2O3}$ from 5.4 grams of $\ce{Al}$ and enough oxygen, the temparture of 2Kg of water climbs by 20 degrees. What's the molar enthlpy of formation of $\ce{Al2O3}$ ?
What I tried:
The balanced reaction:
$\ce{4Al} + 3\ce{O2} => 2\ce{Al2O3} $
5.4 grams of $\ce{Al}$ are 0.2 moles.
If... |
How to determine the sign of the enthlpy of formation? |
During the creation of $\ce{Al2O3}$ from 5.4 grams of $\ce{Al}$ and enough oxygen, the temparture of 2Kg of water climbs by 20 degrees. What's the molar enthlpy of creation of $\ce{Al2O3}$ ?
What I tried:
The balanced reaction:
$$\ce{4Al} + 3\ce{O2} \rightarrow 2\ce{Al2O3} $$
5.4 grams of $\ce{Al}$ are 0.2 ... |
How to determine the sign of the enthlpy of creation? |
During the formation of $\ce{Al2O3}$ from 5.4 grams of $\ce{Al}$ and enough oxygen, the temparture of 2Kg of water climbs by 20 degrees. What's the enthlpy of formation of $\ce{Al2O3}$ (per mole) ?
What I tried:
The balanced reaction:
$$\ce{4Al} + 3\ce{O2} \rightarrow 2\ce{Al2O3} $$
5.4 grams of $\ce{Al}$ a... |
How to determine the sign of the enthlpy of formation? |
Suppose there's a spaceship that has a hole in it. Gas is expanding through the hole from the spaceship to outer space (vacuum). According to pressure volume work ($P\Delta V$) the work done by the gas is infinity. According to my homework assignment, it's 0. Can someone please explain why? |
Why is the work done by gas expanding to space is 0 and not infinity? |
Suppose there's a spaceship that has a hole in it. Gas is expanding through the hole from the spaceship to outer space (vacuum). According to pressure volume work ($P\Delta V$) the work done by the gas is infinity. According to my homework assignment, it's 0. Can someone please explain why?
Edit:
According to Wik... |
Why are thioesters relatively reactive with regard to nucleophilic attack? Prof says to wait until pchem 3 when we learn about orbital symmetry. He also said that sulfur’s d-orbitals (?!) don't have the correct symmetry to participate in resonance with the carbonyl carbon.
Wait. I thought that sulfur didn’t utilize... |
Question 4, iii.) in here:
I get everything up until the sign? How do we know it is a negative sign there? Exothermic reaction? Is it because of the Oxygen, suggesting it's a combustion reaction or no?
http://fc.sjsd.net/~gjohnson/FOV1-000437CE/FOV1-0004A88E/FOV1-0004AAB1/Chemistry%20SL%20paper%202.pdf?Plugin=Loft |
I placed a container with 1000 grams (1 kg) of water at room temperature (20 degrees celsius) Inside a vacuum at 0.03 atm pressure. The water boiled for a few seconds then froze solid.
I need to calculate how much water evaporated before freezing occurred. Anyone know how? |
How much water evaporates In a vacuum before freezing? |
I placed a container with 1000 grams (1 kg) of water at room temperature (20 degrees celsius) Inside a vacuum at 0.03 atm pressure. The water boiled for a few seconds then froze solid.
I need to calculate how much water evaporated before freezing occurred. Anyone know a formula I could use? |
I'm interested in the mushroom cloud, what is this cloud made of ?
![enter image description here][1]
I know that the nuclear reaction is the following I found it in[This web page][2]
$$^{235}U+ ^1_0n\rightarrow \ \ ^{95}Sr+^{139}Xe +2\ ^1_0n+180 MeV$$
I know that this elements are not stable and decay, wh... |
What chemical elements release a nuclear explosion? |
I know GAMESS is not best suited for crystal simulation but I am not ready to start learning another package as VASP. As I heard GAMESS is able to do some calculations in a **"terminated"** crystal (I mean using an ion in the periphery instead of repeating it multiple times). Mostly I need to calculate HOMO-LUMO gap /... |
How to run crystal simulation on GAMESS? |
I've often herd that aryl halides are very less reactive towards nucleophilic substitution reactions. One of the reasons for this I found was that there is resonance effect in the compound, but how is that responsible for it to less reactive towards S.N. reactions and in addition to resonance effect are there other fa... |
Why aryl halides are very less reactive towards nucleophilic substitution reactions? |
What chemical elements release a nuclear explosion ( mushroom cloud)? |
I'm interested in the mushroom cloud, what is this cloud made of ?
![enter image description here][1]
I know that the nuclear reaction is the following I found it in[This web page][2]
$$\ce{{}^{235}U + {}^1_0n -> {}^{95}Sr + {}^{139}Xe +2~{}^1_0n + 180~MeV}$$
I know that this elements are not stable and de... |
Can anyone explain the resonating structure of halo-benzene? How do the electron transfer take place? |
Can anyone explain the resonating structure of halo-benzene? |
During the formation of $\ce{Al2O3}$ from 5.4 grams of $\ce{Al}$ and enough oxygen, the temperature of 2Kg of water climbs by 20 degrees. What's the enthlpy of formation of $\ce{Al2O3}$ (per mole) ?
What I tried:
The balanced reaction:
$$\ce{4Al + 3 O2 -> 2 Al2O3}$$
5.4 grams of $\ce{Al}$ are 0.2 moles.
If... |
How to determine the sign of the enthalpy of formation? |
what is the most accepted explanation of "aurophilicity" shown by gold? |
I would expect that [gilding](https://en.wikipedia.org/wiki/Gilding) - classic manual gold plating using [gold leaf](https://en.wikipedia.org/wiki/Gold_leaf) - works.
(But as the frequency, amplitude and radius of flexing is not known, it's hard to tell)
It would be starting with the polished polymer surface.
... |
Question 4, iii.) in here:
(iii) The equation for an important reaction of ethene is given below.
![Question in photo][1]
[1]: https://i.stack.imgur.com/DWV4z.png
I get everything up until the very end. We need to identify the bond enthalpies first:
c=c = 612
O=O = 248
SUM of these= 860
C-C = 348
2x... |
Can anyone explain the resonating structure of halo-benzene? How does the transfer of an electron from the halogen atom to the α-carbon and from there to ß-carbon and so on take place? |
What is the reasoning behind the resonating structure of halo-benzene? |
What is the most accepted explanation of aurophilicity? |
Question 4, iii.) in here:
(iii) The equation for an important reaction of ethene is given below.
![Question in photo][1]
[1]: https://i.stack.imgur.com/DWV4z.png
I get everything up until the very end. We need to identify the bond enthalpies first:
\begin{align}
\ce{C=C} &= 612\\
\ce{O=O} &= 248\\
\te... |
How to calculate the enthalpy change for the formation of ethylene epoxide from ethylene? |
When dealing with different problems in thermodynamics
I noticed that some of the problem consider the number of moles in calculating the heat absorbed or released, whereas some don't and they deal with the heat,capacity,difference in temperature WITHOUT considering the number of moles
example1: 1 gram of a... |
when do we consider the moles in bomb calorimeter? |
Why is Hydrogen so reactive? What makes it combustible? |
Why is Hydragen gas so highly reactive? |
Why is hydrogen gas so highly reactive? |
I noticed some problems consider the samples in a calorimeter as a solution thereby calculating the mass of the **combining samples**, whereas in others I found that they separate the samples into different calculations by using the **distinct mass** and specific heat for each.
could you explain why?
Thanks|! |
when do we considedr a calorimeter as a solution in calculation? |
Is there a material which can be applied to a surface that will block liquids but is dissolved by blood?
The idea is to use the liquid to close a circuit, but only if blood is present.
I'm wondering if there is something I can coat on the circuit to act as a barrier preventing other liquids from reaching the circ... |
when do we consider the samples in a calorimeter as a solution in calculation? |
So IUPAC has a system for naming organic compounds, ionic compounds, and inorganic compounds. I have seen something vaguely suggesting there is one for metallic compounds. What is it, if it even exists. If it doesn't exist what is the generally accepted way of naming metallic compounds? |
At low concentration, conductivity is proportional to concentration (a linear relationship).
Each ion will have its own unique mobility, as discovered by Kohlrausch. H+ has the highest mobility. As you can see in your graph the acids have higher conductivities than the salts. OH- is also highly mobile.
As con... |
At low concentration, conductivity is proportional to concentration (a linear relationship).
Each ion will have its own unique mobility, as discovered by Kohlrausch. H+ has the highest mobility. As you can see in your graph the acids have higher conductivities than the salts. OH- is also highly mobile.
As con... |
Specifically KF into the K+ and F- ions. I can find tables on the DE into atoms, but where would I go to find the DE between ions?
I am also given that the bond length is 2.17e-10m. Can I use that at all? |
How do you figure out the dissociation energy for ions? |
Specifically $\ce{KF}$ into the $\ce{K+}$ and $\ce{F-}$ ions. I can find tables on the DE into atoms, but where would I go to find the DE between ions?
I am also given that the bond length is 2.17e-10m. Can I use that at all? |
If silicon dioxide tends to form a crystal lattice with four $\ce{O}$'s around a central $\ce{Si}$, why isn't the molecular formula $\ce{SiO4}$ then? I'm confused why it's unique in that its molecular formula doesn't match up with its geometry. |
What is the IUPAC nomenclature for Metallic Compounds? |
![enter image description here][1]
[1]: https://i.stack.imgur.com/icTlb.gif
Critical points are defined (by wikipedia) as the "end-point of the phase equilibrium curve".
I would say this diagram therefore has three critical points. But this is unnatural. I doubt its true.
Other curves are different f... |
How many critical points? Why? |
why is ozone O₃ diamagnetic? |
Why does SiF₄ have a higher melting point than SF₄? |
Is pyrite (FeS₂) an ionic or a covalent compound? |
Is the name "Dihydrogen monoxide" actually what chemists would use to refer to $\ce{H2O}$ (assuming there was no common name, "water")?
Of course, this is all over the internet. I'm a little skeptical though because the similar chemical $\ce{H2S}$ is called "hydrogen sulfide", not "dihydrogen monosulfide". |
> Consider the following reaction
$$\ce{CH3\bond{-}CH\bond{=}CH2 ->T[$\ce{Br2}$/$\ce{NaCl}$]?}$$
What would be the product(s) for this reaction? I am confused because there are two nucleophiles here, $\ce{Br-}$ and $\ce{Cl-}$. So, there are two alternatives for the second step. Let me explain what I ... |
I'm just a simple man curious about things. I've no big understanding of chemistry. I had this question today in mind. What chemicals could I use to achieve the cleanest metallic surface?
For example, I could first start by using isopropyl alcohol to remove all dirt and oils. But there are other liquids such as acet... |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.