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Are the elements lanthanum and actinium considered to be in the d block or the f block of the periodic table? |
Why can singlet oxygen participate in cycloadditions while the triplet oxygen, on the other hand, can't? |
Ugh, I drank orange juice too soon after brushing my teeth and my mouth feels awful!
What causes that foul taste with this combination of toothpaste and orange juice? Is it a reaction between the oil of wintergreen in the toothpaste and the citric acid in the OJ? Is it something else...? What's the explanation for thi... |
Ugh, I drank orange juice too soon after brushing my teeth and my mouth feels awful!
What causes that foul taste with this combination of toothpaste and orange juice? Is it a reaction between the oil of wintergreen in the toothpaste and the citric acid in the OJ? Is it something else...? What's the explanation for t... |
What causes that foul taste with combination of toothpaste and orange juice? |
Ugh, I drank orange juice too soon after brushing my teeth and my mouth feels awful!
What causes that foul taste with this combination of toothpaste and orange juice? Is it a reaction between the oil of wintergreen in the toothpaste and the citric acid in the OJ? Is it something else...? What's the explanation for t... |
> Why do juice taste awful?
Awful taste is due to **sodium laureth sulfate**, also known as **sodium lauryl ether sulfate (SLES)**, or **sodium lauryl sulfate (SLS)**- depending on which toothpaste you use.
SLES and SLS are **surfactants**(wetting agent). Both chemicals are added in toothpaste to create foam a... |
Why can singlet oxygen participate in cycloaddition reactions while the triplet oxygen, on the other hand, can't? |
Today I was trying to clean my laptop with a nail polish remover (ingredients: ethyl acetate, peg-40, hydrogenated castor oil, panthenol, parfum, d-limonene, geraniol, ci 26100, ci 60725). Not only it didn't get clean, but some white thing remained on the keys.
I tried boiling water and a piece of cloth to make it war... |
How to reverse damage done by nail polish remover without acetone to a laptop keyboard? |
Generating mol files from a molecular structure image? |
We know that equilibrium in a chemical system is attained when forward and backward reaction rates are equal. What if the reaction mixtures involve more than one reaction? For example, consider three inter-reacting species A, B and C. The rate constants for the forward and backward reactions of A->B is k1 and k'1, tha... |
I want to study several carbohydrates that includes but not limited to the following molecules:
1) Glucose
2) Galactose
3) Mannose
4) Fructose
5) Tagatose
6) Sorbose
I know that for any carbohydrate, possible list of carbohydrates isomers are
1) Single chain (L and D isomer)
2) $\alpha$ and... |
I want to study several carbohydrates that includes but not limited to the following molecules:
1. Glucose
2. Galactose
3. Mannose
4. Fructose
5. Tagatose
6. Sorbose
I know that for any carbohydrate, possible list of carbohydrates isomers are
1. single chain (L and D isomer)
2. $\alpha$ and $\be... |
When I first learned about substitution reactions, I started wondering something that I never ended up figuring out:
Suppose you have a strong nucleophile which is also a good leaving group, such as I$^{-}$. Can such a group substitute itself using the SN1 mechanism? If so, would that mean if such a group were bonded ... |
Is it possible for a group to substitute itself? |
Considering how electronegative oxygen is, why is the chemical shift of alcohol protons (1H-NMR) not so high? The [chemical shifts of the protons on 3-propanol][1] are about 1.20 for the carbon-1 hydrogens, about 2.2 for the alcohol proton, and about 4.01 for the carbon-2 hydrogens. Why on earth would the electrons on ... |
Why is an alcohol proton so shielded? |
I understand that there are many different catalytic mechanisms that suggest different ways of accounting for the effect of a catalyst on reaction rate. My question is:
Given a termolecular elementary (it is known it is an elementary reaction) reaction of the form:
$$\ce{A + B + C <=> D + E + C}$$
Does the rate of... |
I have come across this trihydroxy propane for glycerol, which I think should've been Propan-1,2,3-triol. Why is it named this way? Is there any other rule of nomenclature working? |
why is the IUPAC name of glycerol in the way it is? |
Calculate the change in enthalpy as 1kg of nitrogen is heated from 1000K to 1500K, assuming the nitrogen is an ideal gas at a constant pressure. The tempreature dependent specific heat of nitrogen is Cp = 39.06 - 512.79T^1.5 + 1072.7T^2 - 820.4T^3 where Cp is in kJ/kg-mol and T is in K
Answer is 697.27 kJ
This is... |
I have come across the name trihydroxy propane for glycerol, which I think should've been Propan-1,2,3-triol.
Why is it named this way? Is there any other rule of nomenclature working? |
Why is the IUPAC name of glycerol expressed in the way that it is? |
> The function looks like its easy to differentiate or integrate. Should I be doing something involving calculus?
Yes, exactly! The equation you should be using is the differential form of the enthalpy equation you are already using.
$$dH = m~C_p(T)~dT$$
$$\int_{H_1}^{H_2} dH = m \int_{T_1}^{T_2} C_p(T)~dT ... |
An air with mass of 0.454kg and an unknown mass of CO2 occupy an 85 Liters tank at 2068.44 KPaa . If the partial pressure of the CO2 is 344.74 kPaa, determine its mass.
Answer is 0.138kg
Ok lets setup Dalton's Law:
P_total = P_air + P_CO2
2068.44 = (mRT/V)_air + 344.74
m_air = 0.454 kg
R_ai... |
I've been investigating chemical kinetics and stumbled across the CHEMKIN program manuals and the JANAF tables. In the original CHEMKIN database they list 'standard enthalpy'. I've checked and this is not in fact enthalpy of formation as this is a separately listed value. What I'm confused about is that I cannot find a... |
Negative and Zero Enthalpy? |
I've been investigating chemical kinetics and stumbled across the CHEMKIN program manuals and the JANAF tables. In the original CHEMKIN database they list 'standard enthalpy'. I've checked and this is not in fact enthalpy of formation as this is a separately listed value. What I'm confused about is that I cannot find a... |
> Why do juice taste awful?
Awful taste is due to **sodium laureth sulfate**, also known as **sodium lauryl ether sulfate (SLES)**, or **sodium lauryl sulfate (SLS)**- depending on which toothpaste you use.
SLES and SLS are **surfactants**(wetting agent). Both chemicals are added in toothpaste to create foam a... |
please tell me which one is true ?
1. px orbital ----> m = -1 , py orbital ----> m = 0 , pz orbital ----> m = +1
; OR
2. py orbital ----> m = -1 ; pz orbital ----> m = 0 ; px orbital ----> m = +1
please tell me which one is true & mention your references. thanks. |
What's the magnetic quantum number for p orbitals ? what's for px , what's for py & what's for pz ? please answer them separately |
When we perform the hydrolysis of cellulose by acid, we already knew that it can convert cellulose into glucose. As we know, cellulose is composed of beta glucose units linked by beta 1,4-glucosidic bonds. So I would like to know, resulting glucose after hydrolysis is beta or alpha glucose? If beta glucose is present, ... |
Can beta D-glucose be present hydrolysate after hydrolysis of cellulose and how can it be converted into alpha D-glucose? |
Benzene shows electrophilic substitution reactions. Normally, anything that can generate a carbocation shows, for example, a Friedel-Crafts alkylation reaction. I wanted to know if this reaction is also possible: taking an aldehyde or a ketone with an acid, which will protonate the oxygen atom and generate a carbocatio... |
I was reading about electronic effects in organic compounds, and I found the explanation that carboxylic acids are weakening as their number of carbon atoms increase. But I found a tabel of Ka for different acids, and it writes that Ka for propanoic acid is 1.34*10^-5 while butanoic acid's acidic constant is 1.48*10^-5... |
Why is propanoic acid weaker than butanoic acid? |
I was reading about electronic effects in organic compounds, and I found the explanation that carboxylic acids are weakening as their number of carbon atoms increase.
But I found a table of $K_a$ for different acids, and it writes that $K_a$ for propanoic acid is $1.34*10^{-5}$ while butanoic acid's acidic constant... |
I was reading about electronic effects in organic compounds, and I found the explanation that carboxylic acids are weakening as their number of carbon atoms increase.
But I found a table of $K_\mathrm{a}$ for different acids, and it writes that $K_\mathrm{a}$ for propanoic acid is $1.34\times 10^{-5}$ while butanoi... |
> The function looks like its easy to differentiate or integrate. Should I be doing something involving calculus?
Yes, exactly! The equation you should be using is the differential form of the enthalpy equation you are already using.
$$dH = m~C_p(T)~dT$$
$$\int_{H_1}^{H_2} dH = m \int_{T_1}^{T_2} C_p(T)~dT ... |
"... catalysis, the acceleration of chemical reactions by substances not consumed in the reactions themselves—substances known as catalysts."
(Source: http://global.britannica.com/science/catalysis)
Now as I've understood, to keep a reaction going, you must keep the solution heated and sometimes add more of the c... |
Why is more of a catalyst added, when it is not consumed? |
**The question is:-**
In which of the following diagrams is the aufbau principle violated:-
![enter image description here][1]
[1]: https://i.stack.imgur.com/qUohQ.jpg
**I have tried to answer this in the following way:-**
Now ignoring the Hund principle, the aufbau principle states that electrons have... |
Is the Aufbau principle violated in the diagram (b)? |
An oxide of chromium used in chrome plating has a formula mass of 100.0 u and contains four atoms per formula unit. Establish the formula of this compound, with a minimum of calculation.
Express your answer as a chemical formula.
So the question tells me that the mass of the Chromium Oxide is 100.0 amu and has 4 ... |
> An oxide of chromium used in chrome plating has a formula mass of
> 100.0 u and contains four atoms per formula unit. Establish the formula of this compound, with a minimum of calculation.
>
> Express your answer as a chemical formula.
So the question tells me that the mass of the Chromium Oxide is 100.0 amu a... |
> I am just wondering how it comes that 60-100% methanol fractions from MCI gel CHP20P eluted very early on C8 column?!
The gel you are using seems to be a porous divinyl benzene / styrene resin. The aromatic groups of the resin may interact more strongly with aromatic side chains on your molecule (e.g. Y residues)... |
We know that equilibrium in a chemical system is attained when forward and backward reaction rates are equal. What if the reaction mixtures involve more than one reaction?
For example, consider three inter-reacting species A, B and C. The rate constants for the forward and backward reactions of $\ce{A -> B}$ are $k_... |
I added a branch to the example shown in the textbook what do you do when your longest carbon chain has a CH2Cl attached to a certain carbon? Previously the book treated it as a methyl group and a halogen but my modification changes the length of the longest carbon chain so how do I name this molecule?)
Now as I've understood, to keep a reaction going, you must keep the solution heated and sometimes add more of... |
I'm looking for a wet etch of Bismuth Oxide that **does not etch Bi itself.**
There are obviously chemicals that etch Bi2O3, but Bi is pretty fragile, so almost everything I've found that can etch Bi2O3 also etches Bi, and usually more rapidly than the Bi2O3 itself.
However, someone recently mentioned to me in pa... |
Is there a selective wet etch of Bi2O3 Bismuth Oxide? |
I'm looking for a wet etch of Bismuth Oxide that **does not etch $\ce{Bi}$ itself.**
There are obviously chemicals that etch $\ce{Bi2O3}$, but $\ce{Bi}$ is pretty fragile, so almost everything I've found that can etch $\ce{Bi2O3}$ also etches Bi, and usually more rapidly than the $\ce{Bi2O3}$ itself.
However, som... |
Nitrogen (k=1.4) is expanded isentropically. Its temperature changes from 620F to 60F. Find the Pressure Ratio:
Answer is 12.91
Simply use Isentropic Relation.
620F = (1799/3) K
60F = (2597/3) K
T1/T2 = (P1/P2)^(k-1/1.4)
(1799/3)/(2597/3) = (P1/P2)^(1.4-1/1.4)
(1799/3)/(2597/3)^(1.4/1... |
> Nitrogen (k=1.4) is expanded isentropically. Its temperature changes
> from 620°F to 60°F. Find the Pressure Ratio:
Answer is 12.91
Simply use Isentropic Relation.
$$620°F = (1799/3) K$$
$$60°F = (2597/3) K$$
$$\frac{T_1}{T_2} = \frac{P_1}{P_2}^{\frac{k-1}{1.4}}$$
$$\frac{(1799/3)}{(2597/3)} = \frac{P_... |
The reaction of alcohols $\ce{ ROH }$ with $\ce{ PCl5 }$ and $\ce{ PCl3 }$ yields an alkyl halide $\ce{ RCl }.$
With $\ce{ PCl5 }$ the reaction is quite simple leading the formation of $\ce{ RCl }$ and $\ce{ POCl3 }.$
But with $\ce{ PCl3 }$ a problem arises. Since $\ce{ PCl3 }$ has both a lone pair and vacant $3... |
Oh, I was just reading about this. This excerpt points out the factor contributing to the chemical shift observed in alcohols
> The extent of hydrogen bonding varies with concentration, temperature, and solvent, and changes in the degree of hydrogen bonding can cause substantial shift changes. This is very evident ... |
I added a branch to the example shown in the textbook. What do you do when your longest carbon chain has a $\ce{CH2Cl}$ attached to a certain carbon?
Previously the book treated it as a methyl group and a halogen but my modification changes the length of the longest carbon chain so how do I name this molecule?
!... |
I would strongly recommend to consult the references I mentioned in this answer earlier: http://chemistry.stackexchange.com/questions/33164/r32-space-group-crystallography
In particular have a look at the meaning of the individual symbols and how space groups are represented in these kinds of diagrams. Again, the In... |
what is the major product of the reaction given? |
I added a branch to the example shown in the textbook. What do you do when your longest carbon chain has a $\ce{CH2Cl}$ attached to a certain carbon?
Previously the book treated it as a methyl group and a halogen but my modification changes the length of the longest carbon chain so how do I name this molecule?
!... |
I would strongly recommend to consult the references I mentioned in this answer earlier: http://chemistry.stackexchange.com/questions/33164/r32-space-group-crystallography
In particular have a look at the meaning of the individual symbols and how space groups are represented in these kinds of diagrams. Again, the In... |
I would strongly recommend to consult the references I mentioned in this answer earlier: http://chemistry.stackexchange.com/questions/33164/r32-space-group-crystallography
In particular have a look at the meaning of the individual symbols and how space groups are represented in these kinds of diagrams. Again, the In... |
Recently, while cleaning a neighbour's fridge (turned off for a few weeks), I came across a cup (closed with a lid). Inside the cup was, to my olfactory horror, congealed milk, with a teaspoon nicely wedged into it.
The milk had separated into a blue cheese-like solid, overlain with a semi-translucent liquid.
Wh... |
Could milk rust a steel teaspoon? |
Recently, while cleaning a neighbour's fridge (turned off for a few weeks), I came across a cup (closed with a lid). Inside the cup was, to my olfactory horror, congealed milk, with a steel (iron) teaspoon nicely wedged into it.
The milk had separated into a blue cheese-like solid, overlain with a semi-translucent ... |
Recently, while cleaning a neighbour's fridge (turned off for a few weeks), I came across a cup (closed with a lid). Inside the cup was, to my olfactory horror, congealed milk, with a steel (iron) teaspoon nicely wedged into it.
The milk had separated into a blue cheese-like solid, overlain with a semi-translucent ... |
With the correct starting compound, 3-ethyl-2-methylpentan-2,3-diol, predicting the product is tough! Here is the reaction scheme for this compound:
![enter image description here][1]
1. Alkonium cations A and D both equally likely because they are both tertiary. Thus both alcohols should be equally basic.
2.... |
Recently, while cleaning a neighbour's fridge (turned off for a few weeks), I came across a cup (closed with a lid). Inside the cup was, to my olfactory horror, congealed milk, with a steel (iron) teaspoon nicely wedged into it.
The milk had separated into a blue cheese-like solid, overlain with a semi-translucent ... |
Remember your general chemistry. In an acid-base reaction, the equilibrium favors the side of the reaction with the weaker acid/base pair. Strong bases have weak conjugate acids. Strong acids have weak conjugate bases. Weak bases have strong conjugate acids. Weak acids have strong conjugate bases. Consider the followin... |
How do the 1,3 dipolar additions follow the endo rule as in the reaction below where the anti diastereoisomer is formed predominantly?
![enter image description here][1]
[1]: https://i.stack.imgur.com/DWhsc.gif |
Remember your general chemistry. In an acid-base reaction, the equilibrium favors the side of the reaction with the weaker acid/base pair. Strong bases have weak conjugate acids. Strong acids have weak conjugate bases. Weak bases have strong conjugate acids. Weak acids have strong conjugate bases. Consider the followin... |
Recently, while cleaning a neighbour's fridge (turned off for a few weeks), I came across a cup (closed with a lid). Inside the cup was, to my olfactory horror, congealed milk, with a steel (iron) teaspoon nicely wedged into it.
The milk had separated into a blue cheese-like solid, overlain with a semi-translucent ... |
To give this question context, I work in a restaurant and sometimes I'm in charge of getting all of the gum off of the tables at work. Don't mind the work, but I'd be interested in hearing what makes gum so sticky and if there is any chemical I can use to make the cleaning a bit easer and why that chemical works.
I ... |
Why is gum so sticky and what chemicals make for easy removal of gum? |
Studying biochemistry I noticed that equilibrium is reached for K and Na separately (not taking into account electric potential), as would be the case I assume for any molecule or atom. This is of course entropy.
Eg: My understanding is, you have two types of atoms, and a membrane separating them, with different con... |
I'm writing a fictional story with early [industrial age](https://en.wikipedia.org/wiki/Industrial_Age) technology where a chemist discovers not only that diamond and graphite are made of the same substance, but that they [differ by crystalline structure](https://en.wikipedia.org/wiki/Allotropes_of_carbon) (cubic vs he... |
Are there any early industrial age methods capable of determining diamond or graphite's crystalline structure? |
I think the substituent of option (a) should attack the meta position as the resultant carbanion gets stabilized by an inductive effect, but no such compound is given. So where am I making a mistake?
![A chemical equation][1]
[1]: https://i.stack.imgur.com/CBG1m.jpg
|
What is the major product of the reaction given? |
> Would 1850's level spectroscopy or other technology of the time be able to demonstrate the crystal structures of carbon (specifically graphite and diamond) without a 1900's understanding of atomic structure?
Yes, using visible light and petrographic microscopes. The field of optical mineralogy was mature enough by... |
![enter image description here][1]
Based on the NMR data, I have determined that the molecule must be 1-phenoxy-2-propanone, however I may be wrong because given the proton NMR, there are only 4 unique carbon environments, however in 1-phenoxy-2-propanone, there are 5 carbon environments. In addition to that, on c... |
I seem to be getting two different answers from my book and my teacher. For PCR, does PCR require a double stranded piece of DNA that you are tryig to replicate, or does it require a circular piece of DNA (i.e. a plasmid). I believe that when we were doing experimens, we used a plasmid. Also, I can't seem to find a sou... |
Confused about PCR? |
My Attempt:
Would we first need to added in CH3I, LiCO3 and DMF in order to add a methyl group?
Consequently, if we add acetyl chloride and AlCl3, would we successfully arrive at 1-phenoxy-2-propanone?
Thank you so much in advance! |
How to get from a phenol to 1-phenoxy-2-propanone? |
> How to get from a phenol to 1-phenoxy-2-propanone?
**My Attempt**:
Would we first need to added in $\ce{CH3I, ~LiCO3}$ and DMF in order to add a methyl group?
Consequently, if we add acetyl chloride and $\ce{AlCl3}$, would we successfully arrive at 1-phenoxy-2-propanone? |
> For PCR, does PCR require a double stranded piece of DNA that you are trying to replicate, or does it require a circular piece of DNA (i.e. a plasmid).
Circular DNA is not required. Double-stranded DNA is, but keep in mind that if you start with a single-stranded DNA that (i) can be primed by an appropriate 'fowa... |
It's well known that undiluted nitroglycerin will explode when subjected to a physical shock. What is happening as a result of the physical shock that sets off the explosive reaction? In particular, why doesn't it explode spontaneously at room temperature without a physical shock? |
Mechanism of reaction in contact explosives? |
Your assignment seems reasonable. One thing to keep in mind is that even though phenyl protons are in different chemical environments, they may be too close to resolve and with a low-field instrument, some may appear as a "blob" of superimposed signals. In this case, the peak from (B) is simply unresolved from that of... |
> For PCR, does PCR require a double stranded piece of DNA that you are trying to replicate, or does it require a circular piece of DNA (i.e. a plasmid).
Circular DNA is not required. Double-stranded DNA is, but keep in mind that if you start with a single-stranded DNA that (i) can be primed by an appropriate 'fowa... |
According to me Fe(+2) should be a better reducing agent because Fe(+2) after getting oxidized will get a stable d5 configuration and Cr(+2) will get d3 configuration. I think half filled d5 configuration is more stable than d3 configuration. Why is is it so? |
Why Cr(+2) stronger reducing agent than Fe(+2) in water? |
According to me $\ce{Fe^{2+}}$ should be a better reducing agent because $\ce{Fe^{2+}}$ after getting oxidized will get a stable $d^5$ configuration and $\ce{Cr^{2+}}$ will get a $d^3$ configuration. I think the half filled $d^5$ configuration is more stable than the $d^3$ configuration. Why is this not so? |
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