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I'm curious to know, what exactly does the 3,4 part of 3,4-methelynedioxymethamphetamine represent? |
What does the "3,4" mean in 3,4-methylenedioxymethamphetamine (MDMA)? |
As the title suggest can you explain how DRS can be used for finding band gap of a material.Below is an DRS output result
![enter image description here][1]
from the figure we can see that at about 465 nm the relfectance drops steeply with respect to wavelength and attain a plateau at around 420 nm. Using above ... |
One mole of a hydrocarbon is combusted. The products obtained are cooled down to STP and occupy a volume of $89.6l$. Oxygen required for conbustion was $145.6l$ at STP. Find the molecular formula of the hydrocarbon.
Let the hydrocarbon be $C_xH_y$. The combustion reaction can be written as:
$C_xH_y + O_2 \rightar... |
Do all metals in metal oxo complexes (eg Fe in Ferrate, Mo in MoO4,...) have positive oxidation states? |
Oxidation state of metal in metal oxo complexes always positive? |
>One mole of a hydrocarbon is combusted. The products obtained are cooled down to STP and occupy a volume of $89.6\:\ell$. Oxygen required for conbustion was $145.6\:\ell$ at STP. Find the molecular formula of the hydrocarbon.
Let the hydrocarbon be $\ce{C}_x\ce{H}_y$. The combustion reaction can be written as:
$$
... |
**First things first**
When we talk about the rate of a reaction, we mean the rate at which the products appear. This means that it is also equal to the disappearance of the reactants. So, when we quantify the rate in terms of reactants, they must be in opposing magnitude. $$rate = \frac {\Delta [product]}{\Delta t}... |
Do all metals in metal oxo complexes (eg $\ce{Fe}$ in Ferrate, $\ce{Mo}$ in $\ce{MoO4}$,...) have positive oxidation states? |
Metal coated plastics are commercially abundant now-a-days. I want to know how they're plated.
Before posting, I did a quick search and found a [nice link][1]. It refers to this process as *metallization*, although I'm not convinced by the term. Is it right ?
That site already provided the basic information. H... |
How metal-plating on plastics is performed? |
I couldn't comment on the name.
I am familiar with vacuum deposition, but i have only come across deposition on silicon, not plastic. the substrate ad metal are put in a vacuum chamber, the vacuum means that now the metal can be evaporated at a much lower temperature, and is then deposited onto the substrate.(see link... |
As the title suggest can you explain how DRS can be used for finding band gap of a material. Below is an DRS output result:
![enter image description here][1]
From the figure we can see that at about 465 nm the reflectance drops steeply with respect to wavelength and attain a plateau at around 420 nm. Using abov... |
What is the principle of diffuse reflectance spectroscopy behind band gap measurement? |
Can we predict in which direction a given molecule will bend plane polarized light?
If I have a molecule with R form in R-S nomenclature does it mean that the molecule will be dextrorotatory or is it to be found by experiments like finding out rate of a reaction by experiments? |
Can we predict Dextrorotatory and levorotatory character of an organic molecule? |
What does it mean in asking the number of lone pairs of central atom when it has an odd number of electrons?
As lone pairs means the no. of non bonding **pairs** of electrons does it exclude the one odd electron if present in the central atom? |
Wha is the number of lone pairs of central atom when it has an odd number of electrons? |
This question arose in my mind because it's given in a book that Pyrene is aromatic. How can it be with 16 pi electrons? So, it should be actually anti-aromatic or is there any special rule for these types of compounds? |
Is there any special rules for checking the aromaticity of polycyclic compounds? |
What is the number of lone pairs of central atom when it has an odd number of electrons? |
This question arose in my mind because it's given in a book that [pyrene][1] is aromatic. How can it be with 16Β Ο electrons? So, it should be actually anti-aromatic or is there any special rule for these types of compounds?
![pyrene][2]
[1]: http://en.wikipedia.org/wiki/Pyrene
[2]: https://i.stack.imgur.co... |
If I have a hydrate, such as copper (II) sulfate pentahydrate, $\ce{CuSO_4} \cdot \ce{5H_2O}$, what is the amount of heat to required to dehydrate it? I assume that it is equal to or greater than the amount of heat required to evaporate the water molecules. Does the required heat vary for every hydrate?
The formula ... |
How much heat is required to dehydrate a hydrate? |
If I have a hydrate, such as copper (II) sulfate pentahydrate, $\ce{CuSO_4 \cdot 5H_2O}$, what is the amount of heat to required to dehydrate it? I assume that it is equal to or greater than the amount of heat required to evaporate the water molecules. Does the required heat vary for every hydrate?
The formula for d... |
Why is there a diagonal line cutting through some of the nonmetals and metalloids on the periodic table in groups IIIA, IVA, VA, VIA, and VIIA?
![Periodic table of elements][1]
Is there any historical background about it?
[1]: https://i.stack.imgur.com/3zpgH.jpg |
>When you are diluting air in the system and/or properly evacuating it, you must consider water temperature. Methane is completely dissolved in water at 42 degrees Fahrenheit (5.5 C) but can be completely released (as a gas) at 58 degrees F (14.5 C). <sup>[(source)][1]</sup>
This would seem to imply that the enthalp... |
I am using a rotary evap. in my lab mainly with Dichloromethane as a solvent.
Usually between experiments I clean with a brush the receiving and boiling flash using soap and water and finally rinse with alcohol.
For the condenser I try to to the same, but it is next to impossible to brush the water serpentine.
I... |
Is there any reduction in size of the orbital for a half-filled orbital? For the p orbital, is only one lobe filled if there is only one electron in the orbital? Is there any difference at all? I'm trying to understand the quantum mechanical model. Thank you in advance! |
Is there any difference between a completely filled orbital and an half-filled one? |
I can see how a double bond and a ring structure can lead to geometric isomerism but can't see the same for steric factors. Could you help? Thank you! |
How can geometric isomerism arise due to steric factors? |
I am using a rotary evaporator ('rotovap') in my lab mainly with dichloromethane as a solvent.
Usually between experiments I clean the receiving and boiling flasks with a brush using soap and water and finally rinse with alcohol.
For the condenser I try to do the same, but it is next to impossible to brush the wate... |
I put 98% white fuming nitric acid and then I pour some sodium bicarbonate expecting NaNO3 being formed, I'm not really using much water because it will make evaporation takes ages, even so NaHCO3 should give NaNO3 when in contact with HNO3 and it seems so, CO2 is formed very quickly so I suppose the reaction is happen... |
I put 98% white fuming nitric acid and then I pour some sodium bicarbonate expecting $\ce{NaNO3}$ being formed, I'm not really using much water because it will make evaporation takes ages, even so $\ce{NaHCO3}$ should give $\ce{NaNO3}$ when in contact with $\ce{HNO3}$ and it seems so, $\ce{CO2}$ is formed very quickly ... |
Does the hydrolysis speed increase when more H+ ions are in the solution?
So if I were to use H2SO4 instead of HCl (same volumes) then H2SO4 will be the most effective? |
Does the hydrolysis speed increase when more H+ ions are in the solution? |
Does the hydrolysis speed increase when more $\ce{H+}$ ions are in the solution?
So if I were to use $\ce{H2SO4}$ instead of $\ce{HCl}$ (same volumes) then $\ce{H2SO4}$ will be the most effective? |
I want to convert cellulose to another form (crystalline => amorphous). Cellulose requires a temperature of 320 Β°C and pressure of 25 MPa to become amorphous in water.(Is the pressure achievable in the lab?)
Is this doable in the lab and how should I begin on reproducing that situation (which tools would I need) ?
... |
Is the current situation possible for recreaction in a lab? |
Is there any reduction in size of the orbital for a half-filled orbital? Is the probability at any point of finding an electron doubled if there are two electrons instead of one? Is there any difference at all? I'm trying to understand the quantum mechanical model. Thank you in advance! |
"If the phosphorus is going to form PCl5 it has first to generate 5 unpaired electrons. It does this by promoting one of the electrons in the 3s orbital to the next available higher energy orbital. Which higher energy orbital? It uses one of the 3d orbitals. You might have expected it to use the 4s orbital because this... |
Why apart from when building atoms in the first place, the 3d is the lower energy orbital? |
"If the phosphorus is going to form PCl5 it has first to generate 5 unpaired electrons. It does this by promoting one of the electrons in the 3s orbital to the next available higher energy orbital. Which higher energy orbital? It uses one of the 3d orbitals. You might have expected it to use the 4s orbital because this... |
When the lone pair of Ammonia is involved in resonance its basicity decreases. But, conjugation with carbonyl group or resonance with benzene, which will reduce the basicity of Ammonia to a greater extent? |
Is it possible to heat a material above its solidus without melting occurring?
More specifically, at a heating rate of approximately 200K/s, will a metal alloy exhibit superheating and if so by what order of magnitude i.e. fractions of a degree versus tens of degrees. What is the mechanism behind this?
There is a... |
Sulfur trioxide violates the octet rule. Upon drawing the Lewis dot structure for sulfur trioxide, we see that the central sulfur atom is bonded to three other oxygen atoms by double covalent bonds. Therefore, sulfur is in fact surrouded by 12 electrons and not 8 as per the octet rule. This is explained by the fact tha... |
When the lone pair of an Amino group $\ce{R-\overset{**}{N}H2}$ is involved in resonance its basicity decreases. But, conjugation with carbonyl group $\ce{R}=\ce{R'CO}$ or resonance with benzene $\ce{R}=\phi$, which one will reduce the basicity of Amino group to a greater extent? |
Ketones are relatively much harder to oxidise, but they do undergo oxidation reactions at extreme temperatures. Our teacher also told us about Popoff's rule which says that during oxidation of unsymmetrical ketones, the $\ce{>C=O}$ group remains with the smaller of the two alky groups.. Could you please give me a hint... |
Measures for acid and base strength
-----------------------------------
First, we need to be clear about 'strong' and 'weak' acids.
In order to measure the strength of an acid relative to water and find out how effective a proton donor it is, we must look at the equilibrium constant for the reaction
\begin{equa... |
Measures for acid and base strength
-----------------------------------
First, we need to be clear about 'strong' and 'weak' acids.
In order to measure the strength of an acid relative to water and find out how effective a proton donor it is, we must look at the equilibrium constant for the reaction
\begin{equa... |
Measures for acid and base strength
-----------------------------------
First, you need to be clear about 'strong' and 'weak' acids.
In order to measure the strength of an acid relative to water and find out how effective a proton donor it is, you must look at the equilibrium constant for the reaction
\begin{eq... |
Are compounds like those found in the description stable in water? |
Here are some standard electrode potentials:-
$$SO_4^{2-} + 4H^+ +2e^-\rightarrow SO_2 +2H_2O\\E^o=0.17V\\
NO_3^-+4H^++3e^-\rightarrow NO+2H_2O\\E^o=0.97V\\
NO_3^-+2H^++e^-\rightarrow NO_2+H_2O\\E^o=0.78V$$
When nitric acid reacts with a metal, either nitrogen dioxide or Nitric oxide is formed? How do you pr... |
Prediction of ionic reduction? |
Are sulfonyl-carboxylates stable in water? |
I believe that Volumetric Analysis and Tetration Theory are not the same subject.
But I need to know what is a main difference between those subjects and what is a main intersection? |
What is a relationship between Volumetric Analysis and Tetration Theory? |
Here are some standard electrode potentials:-
$$SO_4^{2-} + 4H^+ +2e^-\rightarrow SO_2 +2H_2O\\E^o=0.17V\\
NO_3^-+4H^++3e^-\rightarrow NO+2H_2O\\E^o=0.97V\\
NO_3^-+2H^++e^-\rightarrow NO_2+H_2O\\E^o=0.78V$$
When nitric acid reacts with a metal, either nitrogen dioxide or Nitric oxide is formed? How do you pr... |
I am particularly interested in knowing about glucose breakdown. If we artificially burn glucose, will the energy released be the same if it is broken down in steps(like in a living cell)? |
Does it make a difference in energy if a reaction is done in many steps or in one step? |
More questions for my DIY hot air balloon:
What are some very common (i.e. easy to purchase) plastic film materials that have very good flame-retardant properties?
How is the "degree of flame retarding" of a plastic film material rated, so that I can compare materials by their manufacturer's rating?
Are there ... |
Common flame-retardant plastic film materials? |
In molecular orbital theory, the fact that a bonding and antibonding molecular orbital pair have different energies is accompanied by the fact that the energy by which the bonding is lowered is less than the energy by which antibonding is raised, *i.e.* the stabilizing energy of each bonding interaction is less than th... |
How can antibonding orbitals be more antibonding than bonding orbitals are bonding? |
What have you found so far? In a situation like this honestly I would go ahead and research what hot air balloons are commonly made with already. Find somebody more experienced in the hobby and ask them if you can, or even an experienced fire fighter you can get in touch with.
From [wikipedia][1]: "For modern sport ... |
I have a practical question: today I have to clean the oven, and it doesn't have self cleaning burn down mode, nor an official scraper I can use...
It's full of charred grease and sugar. I managed to remove most of the charred grease with cold grease remover. But it seems that reagent has no effect on the black full... |
Which reagent can I use to dissolve carbon? |
Which is more acidic? |
Measures for acid and base strength
-----------------------------------
First, you need to be clear about 'strong' and 'weak' acids.
In order to measure the strength of an acid relative to water and find out how effective a proton donor it is, you must look at the equilibrium constant for the reaction
\begin{eq... |
Why is ethanoic acid more acidic than phenol? |
What is a relationship between Volumetric Analysis and Titration Theory? |
I would appreciate if someone could clarify this for me.
We have products A+B combining to form C+D through the transition state X.
First of all, are all reactions at least virtually reversible? Is the difference between a reversible reaction and an irreversible reaction simply that for the former, βG is small, w... |
I want to convert cellulose to another form (crystalline => amorphous). Cellulose requires a temperature of 320 Β°C and pressure of 25 MPa to become amorphous in water.(Is the pressure achievable in the lab?)
Is this doable in the lab and how should I begin on reproducing that situation (which tools would I need) ?
... |
Would it be appropriate for me to ask the question in the body of this question here? |
I have a Wikipedia account and the people there have a tendency for getting upset over chemical structures that I created using MarvinSketch not conforming to the ACS drawing style.
Is there any way to make MarvinSketch use the ACS drawing style? |
How do I get MarvinSketch to use the ACS style of drawing? |
I have a practical question: today I have to clean the oven, and it doesn't have self cleaning burn down mode, nor an official scraper I can use...
It's full of charred grease and sugar. *I managed to remove 98% of the charred grease with cold grease remover*. But it seems that reagent has no effect on the remaining... |
Which reagent can I use to remove carbon from oven? |
Does the chemical element neon consist of a molecule? For example, oxygen consist of two atoms together. But is that the same with neon? |
Is neon a molecular element? |
Is it possible to predict wether an organic compound will photochemically decompose? And is it also possible to predict in which products it will decompose into? |
Predict photochemical decomposition of organic compound? |
Building on @Philipp and @chipbuster's answers-
##What is Activity?
When we have dilute solutions or small quantities of a gas or other substance, the substance behaves as if the particles are just points, rather than having a size. In these settings we often use a simplified set of equations.
For example, wit... |
Building on @Philipp and @chipbuster's answers-
##What is Activity?
When we have dilute solutions or small quantities of a gas or other substance, the substance behaves as if the particles are just points, rather than having a size. In these settings we often use a simplified set of equations.
For example, wit... |
I recently bought in Italy a bottle of "Alcool puro" which is in fact 95% Alcohol and 5 % Water. So alcohol has a freezing point of -114Β°C and water a freezing point of 0Β°C. How can I calculate then the freezing point of the "Alcool puro"? |
How to get the freeze point of mixed liquids? |
For example, this reaction: $$\ce{2NaOH + H2SO4 -> Na2SO4 + H2O}$$
Suppose $\ce{NaOH}$ has 0.02 mol (20$cm^3$), and $\ce{H2SO4}$ has 0.01 mol (10$cm^3$). So neither is limiting reagent.
Well, I know one way is to find the standard enthalpy of formation of all components and subtract the ones of products from rea... |
For example, this reaction: $$\ce{2NaOH + H2SO4 -> Na2SO4 + H2O}$$
Suppose $\ce{NaOH}$ has 0.02 mol (20$cm^3$), and $\ce{H2SO4}$ has 0.01 mol (10$cm^3$). So neither is limiting reagent.
Well, I know one way is to find the standard enthalpy of formation of all components and subtract the ones of products from rea... |
For example, this reaction: $$\ce{2NaOH + H2SO4 -> Na2SO4 + H2O}$$
Suppose $\ce{NaOH}$ has 0.02 mol (20$cm^3$), and $\ce{H2SO4}$ has 0.01 mol (10$cm^3$). So neither is limiting reagent.
Well, I know one way is to find the standard enthalpy of formation of all components and subtract the ones of products from rea... |
For example, this reaction: $$\ce{2NaOH + H2SO4 -> Na2SO4 + H2O}$$
Suppose $\ce{NaOH}$ has 0.02 mol (20$cm^3$), and $\ce{H2SO4}$ has 0.01 mol (10$cm^3$). Both concentration 1M (standard condition). So neither is the limiting reactant.
Well, I know one way is to find the standard enthalpy of formation of all comp... |
For example, this reaction: $$\ce{2NaOH + H2SO4 -> Na2SO4 + H2O}$$
Suppose $\ce{NaOH}$ has 0.02 mol (20$cm^3$), and $\ce{H2SO4}$ has 0.01 mol (10$cm^3$). Both concentration 1M (standard condition). So neither is the limiting reactant.
Well, I know one way is to find the standard enthalpy of formation of all comp... |
How can osmosis be used to measure molecular weight of macromolecules ? Is it applied practically ? |
$$\ce{H_2O_{(l)} + NaCl_{(s)} ->[\Delta] Na+_{(aq)} + Cl-_{(aq)}}$$
When table salt is placed in water, it dissolves due to the polarity of water molecules. When solvation takes place, negatively polar sides of water molecules attach to $\ce{Na+}$ ions, and positively polar sides of water molecules attach to $\ce{Cl... |
Why is it not dangerous to dissolve NaCl? |
$$\ce{H2O_{(l)} + NaCl_{(s)} ->[\Delta] Na+_{(aq)} + Cl-_{(aq)}}$$
When table salt is placed in water, it dissolves due to the polarity of water molecules. When solvation takes place, negatively polar sides of water molecules attach to $\ce{Na+}$ ions, and positively polar sides of water molecules attach to $\ce{Cl-... |
In our lab, we commonly use a mixture of sulfuric acid and nitric acid to clean borosilicate glassware. I'd like to clean some PTFE pieces in there, too, but not sure if they will dissolve or not.
Does anyone have any first-hand experience with this, and know whether or not a sulfuric acid/nitric acid mixture dis... |
Does a sulfuric acid/nitric acid mixture dissolve PTFE (ie. teflon)? |
I fear that you haven't given enough thought to all the concepts that are included in a Standard Enthalpy of Reaction and how the Enthalpy of Reaction is defined.
The difference between the Enthalpy of Reaction $\Delta_{\mathrm{r}} H$ and the Standard Enthalpy of Reaction $\Delta_{\mathrm{r}} H^{\ominus}$
---------... |
I fear that you haven't given enough thought to all the concepts that are included in a Standard Enthalpy of Reaction and how the Enthalpy of Reaction is defined.
The difference between the Enthalpy of Reaction $\Delta_{\mathrm{r}} H$ and the Standard Enthalpy of Reaction $\Delta_{\mathrm{r}} H^{\ominus}$
---------... |
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