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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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Which alloy forms the thinnest sulfide surface passivation layer?

Metal sulfides seem to often form thick layers on alloy surfaces exposed to molten $\ce{S}$. Are there alloy surfaces capable of passivation with $\ce{S}$ before the layer thickness reaches $\pu{1 nm}$...
Paul Kolk's user avatar
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Is my method of artificial rainfall right$?$

Why don't humans use the concept of artificial rainfall$?$ There are many places in the world that are deprived of rainfall and I have one solution to this. We can throw some electrified sand carrying ...
MathStackexchangeIsNotSoBad's user avatar
1 vote
0 answers
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DIY method for regenerating activated carbon in air filters

I am interested in regenerating activated carbon used in general house-hold air filters. I am looking for a sufficiently efficient and easy method to do this in home setting. A little tinkering in a ...
Imsa's user avatar
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2 answers
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Surface Tension at Critical Temperature and at Boiling point [closed]

I recently did an experiment on finding the surface tension of a liquid at different temperatures, When I was going through my lab manual, I found the following statement: As temperature decreases, ...
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1 answer
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Metallic nanostructures exhibiting charge separation

Mostly ions consist of a few atoms. It is easy to see, why the solids they form must have simple stoichiometries. It is true even for polymeric ions, such as some complicated organic molecular ions as ...
Paul Kolk's user avatar
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AC voltage drift

I am applying AC current to a capacitive electrode and recording the change in voltage over time. I have observed a voltage drift that does not follow any consistent pattern. Sometimes, the drift is ...
Simon's user avatar
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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 ...
AlphaK's user avatar
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1 answer
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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 ...
Rayana's user avatar
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3 answers
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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 ...
Dan's user avatar
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15 votes
3 answers
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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 ...
哲煜黄's user avatar
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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 ...
Kevin Kostlan's user avatar
3 votes
1 answer
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Why is the decomposition of gas on a metal surface at high pressure considered a 0 order reaction?

My textbook says that when ammonia decomposes on a platinum surface at high pressure, the reaction is 0-order. This is because at high pressures, the metal surface gets saturated with ammonia ...
Harjot Dhillon's user avatar
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229 views

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 ...
iron's user avatar
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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 ...
harsh v's user avatar
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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 ...
Rory Majule's user avatar
4 votes
1 answer
163 views

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 ...
Rory Majule's user avatar
1 vote
1 answer
183 views

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 ...
James Chadwick's user avatar
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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 ...
David Moldes's user avatar
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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 ...
hoggywoggy's user avatar
7 votes
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48 views

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 ...
C.X.F.'s user avatar
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1 vote
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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 ...
Evamentality's user avatar
2 votes
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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 (...
Kevin Kostlan's user avatar
1 vote
2 answers
2k views

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 ...
Ashutosh Purohit's user avatar
1 vote
1 answer
210 views

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 ...
woebegone_begonias_'s user avatar
1 vote
0 answers
28 views

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 ...
Okano's user avatar
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0 answers
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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 ...
Katharina Z's user avatar
1 vote
0 answers
24 views

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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1 vote
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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, ...
turqoise's user avatar
1 vote
1 answer
84 views

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 ...
George Albercook's user avatar
3 votes
1 answer
791 views

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 ...
Dario Mirić's user avatar
1 vote
0 answers
62 views

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 ...
Dario Mirić's user avatar
3 votes
1 answer
753 views

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,...
Dario Mirić's user avatar
0 votes
0 answers
70 views

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'...
Polydynamical's user avatar
2 votes
1 answer
606 views

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 ...
gino's user avatar
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4 votes
1 answer
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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 ...
Parallax's user avatar
0 votes
2 answers
381 views

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?
Akshay's user avatar
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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 ...
Dario Mirić's user avatar
1 vote
0 answers
93 views

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} + \...
Dario Mirić's user avatar
4 votes
2 answers
191 views

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 ...
user avatar
1 vote
1 answer
833 views

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 ...
user avatar
4 votes
0 answers
98 views

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 ...
uhoh's user avatar
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6 votes
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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 ...
Samardeep singh's user avatar
0 votes
1 answer
271 views

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} ...
Babu's user avatar
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0 votes
0 answers
38 views

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 ...
Aaradhya Verma's user avatar
2 votes
0 answers
60 views

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 ...
David Morley's user avatar
1 vote
1 answer
75 views

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?
Aaradhya Verma's user avatar
8 votes
1 answer
230 views

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 ...
techno.stan's user avatar
3 votes
0 answers
128 views

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 ...
RIPAN BARUAH's user avatar
0 votes
0 answers
39 views

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 ...
RIPAN BARUAH's user avatar

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