Questions tagged [surface-chemistry]
Surface chemistry is roughly defined as the study of chemical reactions at interfaces between 2 or more phases.
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Does Adsorption Depend On Shape Of The Adsorbent?
I was reading about the Freundlich adsorption isotherm and when I read the equation I was quite confused. It states that
$$x/m=k(p)^{1/n}$$
So basically x is mass of the adsorbate adsorbed, m is mass ...
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Reaction Rate for Surface Reactions [closed]
Assume reactions S1 to S4 in the image. How can I can determine the reaction rate in mol/m2.s with the given Arrhenius parameters?
Cs' and Cs-H are site species on the surface.
Cs' is just an ...
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Does someone know a unique testable questions surrounding 1 of the 5 variables that affect the rate of a chemical reaction? [closed]
I am a year 11 student studying high school chemistry and we are currently studying catalysts.
I am working on an assessment and need to come up with a unique but testable hypothesis surrounding one ...
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If a crystal has alternating layers of different atoms, will it display different properties depending on which layer is exposed?
Many metal diboride compounds like $\ce{MgB2}$, $\ce{TiB2}$, and $\ce{ReB2}$ have laminated crystal structures with alternating sheets of metal atoms and boron atoms. If we polish the surface to ...
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Is gallium slippery at room temperature in an inert atmosphere?
Ice is slippery when it isn't too far below it's melting point because the surface molecules are less loosely bound than the bulk and form a thin liquid layer.
Pressure melting is a much smaller ...
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Why decomposition of gas on metal surface at high pressure considered 0 order
While reading my textbook it says that when ammonia decompose on a platinum surface at high pressure, the reaction is 0 order because at high pressure the metal surface get saturated with ammonia ...
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How to determine the surface reaction rate and equilibrium constant for a reaction between a solid site species and gas species
Consider the following reaction mechanism 1:
S1: $\ce{C-H (s) + H (g) <=> C^\star (s) + H2 (g)}$
S2: $\ce{C^\star (s) + H (g) => C-H (s)}$
S3: $\ce{C^\star (s) + C2H2 (g) => C-H (s) + H(g) ...
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Which reaction occurs in calcium vanadate when it comes in contact with water?
I am a physics student currently studying the electrical properties of $\ce{CaVO3}$ and I have noticed that the surface of my thin film samples, which were originally smooth and transparent, now have ...
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Why is n=1 at a low pressure in the Freundlich Isotherm Equation?
On the topic of adsorption of a gas over a solid, the Freundlich isotherm explains this behaviour in an approximate manner via the following equation
$$ \frac{x}{m} = kP^{1/n} \tag{1} $$
where $x$ is ...
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How do I make a 6-mercapto-1-hexanol (MCH) aqueous working dilution?
I am using 6-mercapto-1-hexanol (MCH) as part of the immobilization procedure for forming a self-assembled DNA monolayer on a gold surface (see the first figure of this paper for a good visual ...
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Methods for immobilization of DNA on gold surfaces?
I've been looking for methods for immobilizing 5'-Thiol modified dsDNA on gold slides. Most of what I've come across suggests using DTT followed by a desalting step or using TCEP. However, I haven't ...
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Why surface tension acts tangentially if there is a net inward force? [closed]
I understand that surface tension is caused by an imbalance of forces for molecules on the surface in comparison to those that lie within. As a result, this creates a net inward force that seeks to ...
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Do "pseudo Van der Waals" gases exist?
In college, when deriving the Langmuir isotherm for gas-solid adsorption, the professor proposed a modified version of the Van der Waals state equation, what he called the "pseudo Van der Waals ...
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What does "acidic" mean in an article on hydrogen boride nanosheets?
From Rojas et al. [1] (emphasis mine):
On the other hand, we found that proton exchange with HB occurs in water with the estimated $\mathrm{p}K_\mathrm{a}$ of $3.5\pm 0.2,$ even after reactive sites ...
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Why all commercial SPR instruments use angular interrogation?
Surface plasmonic resonance biosensor devices are used to measure analyte concentration, kinetics, affinity, and specificity without any need for labels. This technique involves the bonding of the ...
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Can micelles form in a polar-vacuum interface?
As the formation of micelles depends on, among many factors, the difference of polarity/relative permittivity of the solvents involved with the surfactant, I'm wondering if a polar-vacuum system is ...
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Would an effervescent tablet react with itself if ground into a nanopowder?
Effervescent tablets usually are a mixture of a weak acid, base, and binder. When dry there is no reaction. But when placed in water the acid-base neutralization releases CO2 rapidly.
If you ground a (...
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Evaporation Rate of Hydrochloric acid
I'm currently working in a Chemical Plant as an intern, and I was given a task to improve the efficiency of the blower, which is already in place right now, by designing a new blower for the ...
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The cleansing action of soap
My textbook says that:
The formation of micelles takes place only above a particular
temperature called Kraft temperature (Tk ) and above a particular
concentration called critical micelle ...
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Adhesion energy vs free energy of solvation
I am looking to compute the solvation free energy of Pt(111). Experimental data are still rare because the entropic term is hard to measure.
I have found a paper where they use a QM/MM approach to ...
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Stability of Mercaptoundecanoic acid and thiol-PEG stored as solids
I am planning to use Mercaptoundecanoic acid (MUA, 98%) and thiol-PEG (O-[2-(3-Mercaptopropionylamino)ethyl]-O′-methylpolyethylene glycol) for functionalisation of gold nanoparticles.
The SDS ...
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Interaction energy of an hydroxide ion with a Pd surface
I need to estimate the interaction energy of a hydroxide ion with a palladium surface of $-0.6$V in water.
I know that the electric field of a charge $e$ is
$$
E = \frac{1}{4\pi\epsilon}\frac{e}{r^2}
$...
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What is the saturation point of dishwashing soap in water?
I am looking to measure the effect of dishwashing soap on the surface tension of water. To select appropriate values for the concentration of dishwashing soap is to find the saturation point first, ...
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Incompatibility of Helmholtz Double Layer and Redox electrochemistry
In an electric double layer capacitor(EDLC) (or any situation with a Helmholtz double layer) what prevents the ions from being reduced or oxidized like the ions in an electrochemical cell?
If it is ...
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Can Surface Energy Be Negative?
In some sources I read, it is written that surface energy can't be negative. However, this doesn't really make sense since surface energy should be negative if molecules on interphase have lower ...
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Stability of Microemulsions
Unlike emulsions, microemulsions are thermodynamically stable. Its stability is often explained by entropy changes brought about by dispersing liquid in another liquid, however this can't be the whole ...
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How can surface excess be negative?
If we have interphase of two phases $\alpha$ (water) and $\beta$ (air), surface excess is defined as
$$\Gamma_i = \frac{n_{i,\mathrm{tot}} - n_{i,\alpha} - n_{i,\beta}} A = \frac{n_{i,\mathrm{int}}} A,...
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Modified Arrhenius equation in the presence of a heterogeneous catalyst
Suppose we are doing heterogeneous catalysis, for example, between nitrogen and hydrogen to create ammonia in the presence of a solid catalyst, like rhuthenium. It's obvious that the gas molecules don'...
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why Tin/Zinc alloys can be used to solder aluminum and Tin alone does not "wet" the aluminum?
It is impossible to solder aluminum with only tin, tin does not "wet" aluminum surface because of the instantaneous reaction aluminum/oxygen on the surface of the base metal (aluminum). I ...
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How can I prevent and remove oxidation on the surface of liquid Galinstan?
The oxide layer formed on galinstan (or its component of pure gallium) when exposed to air increases wetting and dulls the appearance. Is there a clear liquid material in which a blob of liquid ...
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Why does magnesium hydroxide solution solidify after passage of time?
I have been trying to make a suspension of magnesium hydroxide in water. Around 40% magnesium hydroxide w/w. Initially it is fluid, but as time passes, it solidifies. What is causing this?
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Contact Angle Hysteresis
When solid surface is wetted and dewetted with some liquid, contact angle measured will not be the same. I am not sure what does process of wetting or dewetting have to do with contact angle or why ...
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Owens - Wendt Model for Surface Energy of Solid - Liquid Interface
Owens - Wendt model is used for calculating surface energy on liquid - solid interface and it is given by following equation: $$ \gamma_{sl} = \gamma_s + \gamma_l -2(\sqrt {\gamma_l^d \gamma_s^d} + \...
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LEED - determining surface structures
How can one describe surface structures (before and after adsorption)? I understand the diffraction theory but I have never really tried to determine the structures of samples by myself.
LEED (low ...
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Adsorption on solids - homogeneous/heterogeneous surface definition
How could we define homogeneous and heterogeneous surfaces (rigorously)?
It is among my exam questions (but I could not find any definition in my textbook or on the internet).
I would say the ...
user76255
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Is this the first report that acetonitrile & propionitrile crystals create highly polar nano surfaces? How does one detect or quantify such surfaces?
Phys.org's Titan-in-a-glass experiments hint at mineral makeup of Saturn moon says:
Titan, Saturn's largest moon, is a natural laboratory to study the origins of life. Like Earth, Titan has a dense ...
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Why is there preferential adsorption of a common ion during preparation of colloids by peptization?
There was a similar question asked here on Chem SE, but the answer was not very satisfactory to me, so I am asking a fresh question.
Peptization is the process of creating a colloid from a precipitate ...
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What is the theoretical reason for the dependence of the surface tension on the alcohol concentration in water?
The qualitative sketches I, II and III given
below show the variation of surface tension
with molar concentration of three different
aqueous solutions of$ \ce{ KCl, CH_3 (OH) }$and
$ \ce{CH3(CH2)_{11} ...
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Why does physisorption pass into chemisorption on increasing temperature
I have been told, that on increasing temperature, physisorption passes into chemisorption (with greater Activation Energy, generally). But why does that happen?
Shouldn’t the increment in Temperature ...
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A liquid which climbs out of its pot [closed]
My Russian born wife recently asked me to buy her a skin remedy widely used in Russia. In English this is the oil of a plant called Sea Buckthorn. It is a thin yellow liquid. My wife put some of this ...
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Can suspended solid particulate particles adsorb on surface?
Gaseous and liquid particles adsorb on solid surfaces. Can solid particles suspended in a fluid medium also adsorb on these surfaces in the same manner?
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If something is not hydrophilic, is it necessarily hydrophobic?
Is it possible to create hydrophobic water?
Two species are phobic within some medium under some conditions when they don't here together (cohere if they're the same species; adhere otherwise).
To be ...
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Do lyophilic sols have an electrical double layer?
"There are two factors which are responsible for the stability of lyophilic sols. These factors are the charge and solvation of the colloidal particles".
Quoted from NCERT book of OC
But we ...
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Why is Freundlich adsorption isotherm not valid at high pressures? [duplicate]
I have taken the following from Wikipedia :
Limitation of Freundlich adsorption isotherm :
Experimentally it was determined that extent of gas adsorption varies directly with pressure, and then it ...
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Are oxides of sulphur and carbon adsorbed into limestone/marble?
Oxides of sulphur and carbon are commonly present in the atmostphere in areas close to industries, can such oxides get adsorbed into the surface of limestone and marble and cause discolouration and ...
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How can the difference between surface energy and electrostatic repulsion be calculated in electroplating?
When metals are electroplated unto surfaces, there are a myriad of forces at play. To set a clear example, if one were to electroplate a magnet with a diamagnetic metal such as bismuth, there will be ...
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Practical to measure topography of a large area (mm-scale) with scanning probe microscopy (SPM)?
I'm currently very new to nanotechnology. I do understand that it is possible to achieve an excellent topography image of a sample by SPM. However, is it possible to do SPM over a large area (for ...
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How do lyophilic colloids reduce surface tension?
It's given in my textbook that the surface tension of lyophilic/hydrophilic solutions is lower than water.
But my intuition says, since in lyophilic solutions the interaction between a lyophilic ...
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How thick is the colored oxide layer on heat treated stainless steel? [closed]
When stainless steel is welded, or just heat treated, it will develop a thicker oxide layer, which in some cases is is rainbow colored, but can become so thick as to appear almost black. From the ...
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Viscosity at CMC
What happens to viscosity at critical micelle concentration? Does it increase or decrease abruptly, and if so, what's the reason behind it?
I'm aware of changes in other properties such as ...
