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Why is melting point of Vanadium higher than Iron? |
I've been looking at a dental product for pets, called [MAXI/GUARD Oral Cleansing Gel][1] and it states it uses *zinc ascorbate/taurine*, however in the ingredients I [found elsewhere][2] it instead lists *zinc gluconate*.
> Active Ingredient(s): Deionized water, zinc gluconate, ascorbic acid (vitamin C), methylcell... |
What's the difference between Zinc Ascorbate and Zinc Zinc Gluconate? |
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/AzMXL.jpg
So I've studied Redox concepts but in the exam we are asked questions like these.
How am I supposed to know what the reaction is going to be?
How do I go ahead and assume what oxidation state it's going to be and then form the ... |
How do I go about solving this question? |
How can I determine the size? Are there some software available? The image is available below.
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/R8kHam.png |
What's the difference between Zinc Ascorbate and Zinc Gluconate? |
I’ve been trying to make Iron Acetate to dye leather and I cannot, for the life of me, figure this out experimentally.
I’ve been allowing steel wool to react with pure white vinegar in a sealed glass vessel with a pressure release for about a month. It turns dark black to green which I assume is due to the ferrous a... |
Why doesn't separating the layers change the equilibrium point? |
Colligative properties are defined as the "properties of solutions that depend on the ratio of the number of solute particles to the number of solvent molecules in a solution, and not on the nature of the chemical species present (wikipedia)."
When a solute is dissolved in a solvent, the number of solvent molecules... |
Colligative properties: why does the size of solute not matter? |
> To me, it seems that every other STEM field has models to predict results (physics, thermodynamics, fluid mechanics, probability, etc) but chemistry is the outlier.
What about structural engineering? Within that field, it's quite easy to predict the strength of a beam of known material and dimension, like a steel ... |
I'm trying to understand why most modern FT-IRs have three interferometers. Does this improve the signal in someway or does it have another effect? |
Does increasing the number of interferometers increase signal in FT-IR? |
Is the Hydrogen spectrum only an emission spectrum? |
[This tutorial][1] about ethene's bonds has the following paragraph that I hope someone can paraphrase in a better way:
> The pi bond dominates the chemistry of ethene. It is very vulnerable to attack - a very negative region of space above and below the plane of the molecule. It is also somewhat distant from the co... |
I just learned that atoms of the same element can have different mass because of they are isotopes. If there are two isotopes in which each reacts to form the same thing. Would the mass differ in each of the two reactions? Is there a term for compounds just like the term isotope is for the atoms? |
"Isotopes" in a molecule? |
I'll start by establishing my potentially flawed understanding of solutions:
> A solution is a completely homogenous mixture. That means that the two (or more) substances are evenly distributed throughout the mixture (or the cross-section of the mixture in question), and that this distribution is happening on an ato... |
How does solutions of two liquids work? |
For making a mould out of the bicomponent polyurethane resin kit that I have - I am going to need to take out the mould from its form. The mould is what I am actually making from the bicomponent resin.
I have done this once and i know how hard it is to take out the hardened resin out of the form it was poured into. ... |
What will a polyurethane resin not adhere to? |
I'm writing about the treatment of methane gas, and in one part of the process, the methane gas is dried in a tank called a scrubber. Here, a desiccant called triethylene glycol is used.
Thinking about another desiccant, magnesium sulfate heptahydrate (Epsom salt), the water must be taken away through evaporation b... |
Must a desiccant be made anhydrous before it can be used for drying? |
A graded dose-response relationship is shown below with the drug concentration on the $\log$ scale on the $x$ axis and the response on the $y$ axis :
[![enter image description here][1]][1]
According to [this website][2]:
> Slope: a useful parameter - when it is shallow, it suggests a greater chance of ov... |
What is the meaning of the slope in a graded dose-response curve? |
1) I have watch a [video][1] about lead acid battery and I am very confused about the way the half reactions are labelled. I have learned that oxydation is the loss of electron (so it's the half reaction with the electrons on the right side) and reduction is the gain of electron (so electrons should be on the left side... |
This is a theoretical question that I am struggling to get started on for a seminar discussion. If you were attempting to design an instrument with all the basic components (source, analyzer, detector, sample holder) what type of each component would you use and why? The sample is alternating layers of heavy metal in a... |
How can I determine the size of a Tropolone molecule?
It's a 7 ring aromatic with O on the 1st C and OH on the 2nd C.
Is there some software available? The image is available below.
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/R8kHam.png |
How can I detemine the size of this Tropolone molecule? |
This is my interpretation of an MRI:
There's an external magnetic field and most of the hydrogen nuclei will align themselves with that field (which is the lower energy state) but some are not aligned (which is the higher energy state). A chemist can then direct a wide range of radio waves with different wavelengths... |
How does an MRI work? |
Looking around at various material compatibility charts, they seem quite divided on the compatibility of metallic mercury and polycarbonate. Some sources ([here,][1] [here,][2] or [here][3]) indicate that polycarbonate is resistant to any sort of degradation by mercury. However, other sources ([here,][4] [here,][5] or ... |
Does mercury react with polycarbonate? |
why is the Aluminium bioling point higher than silicon? And why is silicon's melting point higher than aluminium? Si has 4 bonds which are civalent in nature. Al is metal thus possesses ionic bond. Where have not ubderstood the concept? |
why is the Aluminium bioling point higher than silicon? And why is silicon's melting point higher than aluminium? |
We learned in school that state change is a matter of molecules moving faster and faster. And we learned "heat em up, speed em up, spread em out". Why then can some liquids have higher temperatures than some gases? |
Why are some liquids hotter than room temperature gases if liquid and solid molecules move more slowly than gases? |
Why is the Aluminium boiling point higher than silicon? And why is silicon's melting point higher than aluminium?
$\ce{Si}$ has 4 bonds which are covalent in nature. $\ce{Al}$ is metal thus possesses ionic bond.
Where have I not understood the concept? |
Why is the aluminium boiling point higher than silicon? And why is silicon's melting point higher than aluminium? |
I am attempting to calculate the distance between molecules of 2-nitrobenzaldehyde in a particular concentration of a solution. My first instinct was to treat the solution as a system of spheres surrounding 2-NB molecules, the size of which would be dictated by the concentration. Obviously such a calculation of the dis... |
When calculating the distance between molecules in a solution, is it reasonable to approximate a sphere around each molecule? |
I'm looking into PCB etching,which requires ferric chloride (There are other etchants, but they're pretty hard to come by where I live and too expensive if I can find them).
The issue is that where I live, only anhydrous ferric chloride is sold (Which is stupid. They don't even label it properly as anhydrous - got... |
I am attempting to calculate the average distance between molecules in a particular concentration of a solution. My first instinct was to treat the solution as a system of spheres surrounding the solute molecules, the size of which would be dictated by the concentration. Obviously such a calculation of the distance bet... |
I am wondering how to use the Gompertz model in modelling drug diffusion:
x(t)=xmax exp(-a exp (b log t))
x(max) is to be taken as 100, a is the undissolved proportion at time t=1. But what is b? I've seen it variously described as half of the max asymptote, the *m* of the linear portion of the graph, or the *m* ... |
What is b in the Gompertz model? |
I am wondering how to use the Gompertz model in modelling drug diffusion:
$$x(t) = x_\mathrm{max}\exp(-a\exp(b\log t)).$$
$x_\mathrm{max}$ is to be taken as $100,$ $a$ is the undissolved proportion at time $t = 1.$ But what is $b?$ I've seen it variously described as half of the max asymptote, the $m$ of the line... |
I made a mistake. I put my ice cream in the refrigerator instead of the freezer and left it there for a night. I realized my folly the next day.
I put it in the freezer. When I took it out, I noticed it had a bunch of ice crystals inside it and on its surface. This intrigued me (not that it is a new discovery of mi... |
If I were to have two seperate containers with solutions of different concentrations with a small opening, most of the molecules would flow down the concentration gradient. Does this occur just because there are more molecules that can pass thru the opening or is there a force pushing them out? Second question would be... |
Whats the driving force behind simple diffusion? Is it just the count of molecules? |
If I were to have two separate containers with solutions of different concentrations with a small opening, most of the molecules would flow down the concentration gradient. Does this occur just because more molecules can pass through the opening or is there a force pushing them out?
My second question is if the mole... |
'Mercury' was included in one of the possible answers for this exam question:
> Name a metal that an inert electrode could be made from.
My answer was 'platinum' which was also a possible answer, but I’m curious how mercury, which is a liquid metal, could be used as an electrode during electrolysis?
[![enter i... |
How can I determine the size of this Tropolone molecule? |
>The explanation was that the zinc metal transferred electrons to copper which in turn reduced the zinc ions in solution, but this does not seem to make any sense as the zinc is being oxidized to just be reduced again. Why does this happen. Is a thin zinc layer more stable?
Your intuition is correct and both of the ... |
What are angular and radial nodes? |
Few quick questions from a chemistry noob.
1. I find [these type of diagrams][1] easier to consult when building molecules using a 'molecular building kit'. Is there a name for this type of diagram?
2. For the glucose molecule (in the above diagram), i noticed the order of H, and OH bonds are not in the same or... |
I understand that oxymercuration-demercuration is textbook Markovnikov. However in a case like this, where the OH is formed on the least substituted carbon (secondary) rather than the most substitued (tertiary because of the methyl group), what could be the explanation?
I thought that the H2O always attacked the mo... |
In what case would H2O attack the least substituted in an oxymercuration demercuration reaction? |
I understand that oxymercuration–demercuration is textbook Markovnikov. However, in a case like this, where the $\ce{OH}$ is formed on the least substituted carbon (secondary) rather than the most substituted (tertiary because of the methyl group), what could be the explanation?
I thought that $\ce{H2O}$ always att... |
In what case would water attack the least substituted carbon in an oxymercuration–demercuration reaction? |
1. I find [these type of diagrams][1]
> [![The glucose molecule structure][2]][2]
easier to consult when building molecules using a 'molecular building kit'. Is there a name for this type of diagram?
2. For the glucose molecule (in the above diagram), I noticed the order of H, and OH bonds are not in the... |
At a high temperature, water is evaporated from the saturated solution by heating. What is the solution losing exactly by the fact that the water left the saturated solution? Does it affect its concentration...solubility?
I have a two thoughts. First, as water evaporated, the amount of dissolved substance 'inside t... |
There are some great answers to this question already, but I'd like to provide a more practical boots-on-the-ground answer from my own perspective as an organic chemistry PhD who did computational chemistry on the side.
Most fields at their cutting edge are unpredictable
--
It has been my observation that when you... |
I try to understand, from the *electromagnetic side only*, how the molecule could be more stable than each atom, and concluded that it could not. Where is my mistake ?
Here is an illustration :
By using a ruler in order to have an "example" of numerical values, we conclude, by taking the numerical values of dista... |
About covalant bound for molecule : repulsion of electrons? |
For the dissociation of a weak acid:
$$\ce{HA(aq)<=>H+ + A-}$$
To calculate $\mathrm{pH}$ of a weak acid, we use the expression: $$K_\mathrm{a}=\ce{\frac{[H+] [A-]}{HA}}$$
The $\ce{[H+]}$ has two sources:
1) Water
2) Acid
Now, many problems that I've read on the calculation of $\mathrm{pH}$ of weak acids t... |
I was reading salt hydrolysis of a salt made from strong acid and weak base. I came across the hydrolysis of $\ce{NH_4Cl}$. These reactions were mentioned
>$$\ce{NH_4Cl + H_2O<=>NH_3 + HCl \tag{R1}}$$
$$\ce{NH_4+ + Cl- + H_2O<=>NH3 + H+ + Cl-}\tag{R2}$$
$$\ce{NH_4+ + H_2O<=>NH3 + H3O+\tag{R3}}$$
$\ce{H+}$ and... |
ERROR: type should be string, got "\r\nhttps://en.wikipedia.org/wiki/Halogen\r\n\r\nCan Halogens react with each other?\r\n\r\nExamples :\r\n\r\n\r\nChlorine + Flourine\r\n\r\n\r\n\r\nFlourine + Iodine\r\n\r\n\r\n\r\nIodine + Bromine\r\n\r\n\r\n\r\nChlorine + Bromine\r\n\r\n\r\n\r\nand so on.\r\n\r\nPermutations and Combinations.\r\n\r\nChlorine + Flourine =\r\n\r\nChlorine + Bromine =\r\n\r\nChlorine + Iodine =\r\n\r\nFlourine + Bromine =\r\n\r\nFlourine + Iodine =\r\n\r\nBromine + Iodine =\r\n\r\nWhat will be the chemical reactions & applications?" |
Will the entropy change be equal if a state change is brought about reversibly and irreversibly? |
20g of water is evaporated from 200g of saturated solution of KNO3(aq) at 60°C by heating and the solution was cooled to 20°C. How many grams of KNO3 were deposited? The solubility of KNO3 in 100g of water is 32 at 20°C and 109 at 60°C.
I have a doubt on "20g water is evaporated from 200g KNO3" statement. I'm assumi... |
Which forms of mass spec will determine accurate concentrations of metal ions in a sample? Preferable not using GC/MS but can MALDI ToF or quadrupole do this somehow. Also, not relative concentration but actual concentration. |
How can mass spectrometry be used to determine concentration? |
20g of water is evaporated from 200g of saturated solution of KNO3(aq) at 60°C by heating and the solution was cooled to 20°C. How many grams of KNO3 were deposited? The solubility of KNO3 in 100g of water is 32 at 20°C and 109 at 60°C.
I have a doubt on "20g water is evaporated from 200g KNO3" statement. I'm assumi... |
20g of water is evaporated from 200g of saturated solution of KNO3(aq) at 60°C by heating and the solution was cooled to 20°C. How many grams of KNO3 were deposited? The solubility of KNO3 in 100g of water is 32 at 20°C and 109 at 60°C.
I have a doubt on `"20g water is evaporated from 200g KNO3"` statement. I'm assu... |
why is the gap between the first two orbits greater than the gap between second and third orbit?
shouldn't the gap keep decreasing as the radius keeps increasing? Can someone explain this ?
|
why does the gap between the energy levels of a hydrogen atom keep decreasing as we move further and further away from nucleus? |
In chemical thermodynamics, the condition "constant temperature and pressure" appears almost everywhere. However, I felt a small ambiguity in the phrase so I wanted to clear my doubts. When we say "constant $T$ and $p$" in chemical thermodynamics, which of these two statements do we actually mean?
- $T$ and $p$ are... |
20g of water is evaporated from 200g of saturated solution of KNO3(aq) at 60°C by heating and the solution was cooled to 20°C. How many grams of KNO3 were deposited? The solubility of KNO3 in 100g of water is 32 at 20°C and 109 at 60°C.
I have a doubt on `"20g water is evaporated from 200g KNO3"` statement. I'm assu... |
QM9 dataset contains about $134000$ small organic molecules with following properties computed using DFT approaches:
# properties
A = "rotational_constant_A"
B = "rotational_constant_B"
C = "rotational_constant_C"
mu = "dipole_moment"
alpha = "isotropic_polarizability"
homo = "homo"... |
20g of water is evaporated from 200g of saturated solution of KNO3(aq) at 60°C by heating and the solution was cooled to 20°C. How many grams of KNO3 were deposited? The solubility of KNO3 in 100g of water is 32 at 20°C and 109 at 60°C.
I have a doubt on `"20g water is evaporated from 200g KNO3"` statement. I'm assu... |
QM9 dataset contains about $134000$ small organic molecules with following properties computed using DFT approaches:
A = "rotational_constant_A"
B = "rotational_constant_B"
C = "rotational_constant_C"
mu = "dipole_moment"
alpha = "isotropic_polarizability"
homo = "homo"
lumo = "lumo... |
QM9 dataset contains about $134000$ small organic molecules with following properties computed using DFT approaches:
A = "rotational_constant_A"
B = "rotational_constant_B"
C = "rotational_constant_C"
mu = "dipole_moment"
alpha = "isotropic_polarizability"
homo = "homo"
lumo = "lumo... |
The effect is a consequence of the Coulomb law for the interaction of the proton and electron, $\displaystyle V(r)=-\frac{e^2}{4\pi\epsilon_o}\frac{1}{ r}$ producing (quantised) energy $\displaystyle E(n)=-hcR\frac{1}{n^2}$, where $n=1,2\cdots$. (That the energy does not depend on angular momentum quantum number $l$ is... |
The effect is a consequence of the Coulomb law for the interaction of the proton and electron; potential energy $\displaystyle V(r)=-\frac{e^2}{4\pi\epsilon_o}\frac{1}{ r}$ producing (quantised) energy $\displaystyle E(n)=-hcR\frac{1}{n^2}$, where $n=1,2\cdots$. (That the energy does not depend on angular momentum quan... |
I am asking on behalf of a friend so please bear with me!
----------
> Instructions:
>
> 1) For each chemical, classify whether it is a VOC (Volatile Organic
> Compound) and/or PM (Particulate Matter 2.5 or Particulate Matter 10).
>
> 2) A chemical can sometimes be both VOC and PM, they are not mutuall... |
In the article on [dilution][1], Wikipedia has the following statement:
> The same direct relationship applies to gases and vapors diluted in air for example. Although, thorough mixing of gases and vapors may not be as easily accomplished.
I was wondering if there is any supporting evidence for the second stateme... |
Is it easier to mix a solution that is in the liquid or in the vapor phase? |
I am trying to understand the different behaviors of sugar syrups when it comes to candy making. Specifically, maple syrup vs molasses.
In making maple candy, pure maple syrup is heated to soft ball stage, which is 235F or about 113C. It is then cooled without stirring to 175F (79.5C), then beaten until it becomes ... |
Does helium freeze at absolute zero? In theory, it should, since all random motions of particles stops at absolute zero, right? |
Does helium freeze at absolute zero? |
Polyvinylalcohol is sold in different forms, one of those is **4-88**.
What means that number? |
Polyvinylalcohol 4-88, what means the numbers? |
$4$ is the viscosity (in $mPa.s$) of a $4$% solution in water at $20°C$
$88$ is the percentage of moles of acetate ester that were hydrolyzed, since polyvinyl alcohol [is manufactured by hydrolysis of polyvinyl acetate][1]. This means that it is an indicator of its purity.
Source: you can check [the catalogue at ... |
$4$ is the viscosity (in $mPa.s$) of a $4$% solution in water at $20°C$. This value is *somewhat* proportional to the molecular weight of the polymer chain.
$88$ is the percentage of moles of acetate ester that were hydrolyzed, since polyvinyl alcohol [is manufactured by hydrolysis of polyvinyl acetate][1]. This mea... |
The value $\bf{4-88}$ can be described as follows:
>$\bf{4}$: This represents the viscosity (in $\pu{mPa s}$) of a $4\%$ solution in water at $\pu{20 ^\circ C}$. This value is *somewhat* proportional to the molecular weight of the polymer chain.
>
>$\bf{88}$: This represents the percentage of moles of acetate este... |
Polyvinylalcohol is sold in different forms, one of those is **4-88**.
What does that number mean? |
What does the number 4-88 mean in "Polyvinylalcohol 4-88"? |
For the reaction of phosphorous acid ($H_3PO_3$) and potassium
hydroxide ($KOH$), write (a) the balanced molecular equation
and (b) the net ionic equation. Note that phosphorous acid is
a diprotic acid.
a. $H_3PO_3(aq) + 2KOH (aq) \longrightarrow 2H_2O(l)+K_2HPO_3 (aq)$
b. $H_3PO_3(aq) + 2OH^{-1}(aq) \longrigh... |
For the reaction of phosphorous acid ($\ce{H3PO3}$) and potassium
hydroxide ($\ce{KOH}$), write (a) the balanced molecular equation
and (b) the net ionic equation. Note that phosphorous acid is
a diprotic acid.
$$\ce{H3PO3(aq) + 2KOH (aq) -> 2 H2O(l) + K2HPO3 (aq)} \tag{a}$$
$$\ce{H3PO3(aq) + 2 OH-(aq) -> 2 H2... |
The mass of Carbon-12 atom is 12.0000000 a.m.u. For relative isotopic mass, e.g. Mg-24 atom is 24 compare with the c-12 as standard. However, why is it unitless? Shouldn't it be 24 a.m.u.? |
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