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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questions
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What is the influence of citrate on PEG-modified polyacrylamide hydrogels?
I've been having a puzzle explaining the experimental results with the citrate anions and PEG modified polyacrylamide:
According to the experimental data there is a hydrogel swelling whenever citrate ...
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23 views
surface energy versus surface tension and contact angles
I am hoping to measure the surface tension between two fluids (salt water and isopropyl alcohol), by measuring the appropriate contact angles, and applying Young's equation: https://en.wikipedia.org/...
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1answer
62 views
Finding the Freundlich adsorption isotherm from the graph of log(x/m) v/s log(p)
The following problem was asked in JEE Mains 2020 (Sept 2, Shift 1),
The mass of gas adsorbed, $x$, per unit mass of adsorbate, $m$, was measured at various pressures, $p$. A graph between $\log\frac ...
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Thermodynamics of micellisation
Micellisation is found to be spontaneous i.e. $\Delta G < 0.$ It's found that $\Delta S > 0,$ which was intuitive since, solvated molecules are released. And, it may be most loosely started that ...
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Doubt's regarding inputting surface reaction for Chemkin Pro
I want to simulate the reaction of a mixture of ethanol and Hydrogen Peroxide on $\ce{Pt}$ using Chemkin Pro. I want to create a surface input files which will include surface reaction mechanism of ...
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1answer
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Am I getting the details of mechanism of adsorption right?
Particles on the surface of a substance have a net force towards the geometric center of the substance called residual force.
When molecules come close enough to the surface of a substance the ...
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36 views
Correlation between redox pseudocapacitance, surface area, and cell potential with metal oxide electrodes
I'm having difficulty intuitively reconciling two different ideas concerning metal oxide thin films in contact with aqueous solutions:
1) that charge storage by both redox pseudocapacitance and ...
2
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1answer
199 views
Why is a drop of chloroform stretched/pulled apart on a water surface?
I distributed drops of chloroform (with a lipid in them) on water (in a Langmuir-Blodgett trough). The chloroform drops form a layer on the water (so that the lipids are distributed on the water ...
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39 views
Effect of solutes on surface tension
What happens to the surface tension of a solvent, say, water when we mix a solute in it?
For the sake of concrete discussion, the examples that I encountered in a test were sodium chloride $(\ce{NaCl})...
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1answer
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The dissociation of hydrogen on UO2 and PuO2 surfaces: Homolytic or heterolytic?
I have seen that $\ce{H2}$ can dissociate on a metal-oxide surface by two methods:
Heterolytically, forming a proton-$\ce{O}$ bond ($\ce{OH}$ group) and a hydride-metal bond ($\ce{M-H}$) on a metal-...
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1answer
36 views
Chemicals to increase surface tension of water
I want to increase the surface tension of water by 1.2 - 2 times. How about adding one or more chemical substances to the water that can possibily increase its surface tension by the desired amount? ...
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Why does silver stick to the glass in Tollens' test? [duplicate]
Why does it not simply form a solid powder at the bottom of the flask?
Does silver also stick to the glass in other silver precipitating reactions?
EDIT:
My question is definitely not the same as ...
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1answer
208 views
Why are van der Waals' forces between gas molecules strong near its critical temperature?
My textbook says
…easily liquefiable gases i.e. with higher critical temperatures are readily adsorbed as van der Waals' forces are stronger near the critical temperatures.
What I do understand is ...
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1answer
34 views
Can Ferrofluids vaporise to gaseous state and Condense back to liquid state and do it many times over? [closed]
Here is the Link for Ferrofluids for basic idea. After going through this Wiki link, probably many people will come to a conclusion like when Ferrofluid boils, its carrier liquid vaporises and nano ...
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Work function changes with adsorption
This is the question
Observation: (0001) is close packed structure of hcp lattice, in fact this plane has the highest work function in all planes of hcp. When O is adsorbed it donates electron ...
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Temperature Programmed Disorption
For second part of the question I'm wondering if the peaks on the right denote the chemisorbed layer, while the peaks on the left denote the physisorbed layers. Since chemisorption results in a ...
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what makes a colloid particles lyophilic or lyophobic?
Why do some colloids don't precipitate(lyophilic) and some do(lyophobic)? Why is gold lyophobic, why does it need protective colloids also why does NaCl cause precipitation in gold sol?
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1answer
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Difference between vapor-phase transport and vapor-phase deposition?
I am currently studying the textbook Physics of Photonics Devices, Second Edition, by Shun Lien Chuang. In a section discussing The Invention of Semiconductor Lasers, the author says the following:
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2answers
241 views
Electric double layer formation
What textbook states about the formation of electric double layer:
When silver nitrate solution is added to potassium iodide solution the precipitated silver iodide adsorbs iodide ion from ...
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59 views
What is the logic behind the terminology lyophilic and lyophobic colloids?
Its given in my text book that-
Colloidal dispersions of starch,rubber,proteins etc are lyophilic colloids whereas colloidal dispersions of metals,sulphides etc are lyophobic in nature.
But even ...
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1answer
340 views
Hardy Schulze Rule
There was a question which was asked in JEE Main 2020 held on 8th January. The question was:
As per Hardy–Schulze formulation, the flocculation values of the
following for ferric hydroxide sol ...
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1answer
953 views
Why Freundlich adsorption isotherms fails at high pressure conditions?
Experimentally it was determined that extent of gas adsorption varies directly with pressure, and then it directly varies with pressure raised to the power 1/n until saturation pressure Ps is reached. ...
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1answer
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Surface energy for different crystallographic planes
For a given crystal structure, say body centred cubic, on what factors does surface energy of each plane depend?
A basic approach considers the atomic density on each crystallographic plane, the ...
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1answer
58 views
Acid-Temperature coagulation of milk
I was making coffee with a cup of boiling milk which was 2 days old. I used instant coffee powder and some sugar for the making of it. Tried to make a very hot coffee but usually prefer medium hotness....
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1answer
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Is activated charcoal an air purifier?
It's well known that activated charcoal is an adsorbent and due to very big surface area per unit of mass it can adsorb a lot of particles.
Let's take as an example for my question this product on ...
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1answer
76 views
Relation between rate of adsorption and the critical temperature of a gas [duplicate]
How is the rate of adsorption related to the critical temperature of a gas? My textbook says more the critical temperature, better are they adsorbed. But I cannot really understand why. They threw in ...
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Does Coagulation depends on nature of Electrolyte?
I am not talking about Hardy Schulz Rule .
Suppose if i add an electrolyte to a colloidal solution. If that electrolyte contain same ion that of colloidal particle due to preferential adsorption is ...
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0answers
177 views
Mechanism of Peptization [closed]
Can somebody please explain the mechanism of Peptization(or give a link to the website which explain the mechanism step by step). The Mechanism given in my book is somewhat different from the ...
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0answers
19 views
Epoxy-silane-coated glass applications or the preparation or quality control for the silanized glass
The task is to make myself (3-Glycidyloxypropyl)trimethoxysilane (GMPTS for short) covered microscope slides to immobilize antibodies.
Each time I cover the freshly prepared slide with Ab, I get ...
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1answer
53 views
Does bicarbonation require water?
In an aqueous solution of $\ce{NaOH}$ exposed to the atmosphere one can probably expect some degree of $$\ce{NaOH(aq) + CO2(g) -> NaHCO3 (aq)}$$
But, what would happen if just a solid block of $\...
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4answers
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Is “stainless” a bulk or a surface property of stainless steel?
In particular, if I cut a block of stainless steel in half, would the newly formed faces be stainless as well?
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1answer
128 views
Why does Freundlich adsorption isotherm not have a term for surface area?
Why does Freundlich adsorption isotherm not have a term for surface area?
The formula given by Freundlich adsorption isotherm:
$$ \frac{x}{m}= k P ^{1/n}$$
Where $x$ is the mass of gas adsorbed ...
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2answers
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How to remove stain from pavement after having dropped sulfuric acid on it?
I had this car battery that flipped in my car trunk.
When I got it out of there it spilled some acid on the pavement. It's a sulfuric acid battery. I added some baking soda on it and poured some more ...
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2answers
319 views
How to reduce surface tension of oil?
I would like to create tiny colored drops slowly falling down in a transparent liquid.
The diameter of the droplets must be around 2mm, and their speed must be approximately 0.5 mm / sec.
For that, ...
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Can pi backdonation occur on non-metal centers?
The common example of back-donation is the interaction of a CO molecule with a metal center (d-orbitals) on a surface.
Can a similar mechanism occur between CO and a non-metal center, like oxygen on ...
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2answers
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What are molecular species?
I am in high school learning about adsorption for the first time. My school textbook says:
"The accumulation of molecular species at the surface rather than in the bulk of a solid or liquid is ...
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1answer
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Nanocar racing competition and the race tracks used
In the Nanocar race competition the molecules are raced on a gold surface.
Is there a specific property of gold that it forms a good "racetrack"? On what criteria does it compare with other metal ...
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1answer
53 views
What decides the nature of emulsifying agents?
I read
The emulsifying
agent forms an interfacial film between suspended particles and the
medium. The principal emulsifying agents for O/W emulsions are
proteins, gums, natural and ...
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0answers
205 views
Calculating pre-exponential factor using transition state theory
I would like to calculate the pre-exponential factor of a surface reaction using transition state theory. I've seen two ways to calculate it but I get different answers for each method (and I don't ...
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332 views
Helmholtz double layer
I don't quite understand what is meant by the Helmholtz double layer.
Textbooks states something along the lines of:
the colloidal particles attain charge by selective adsorption, due to
this it ...
3
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2answers
91 views
Surface Chemistry - Dipole Moment of Surfactant with Water and Phases of a Monomolecular Layer
Recently, I have been trying to study surface chemistry and I have come across questions that I do not understand how to answer. I understand what a dipole moment is, defined as a charge separation ...
2
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1answer
55 views
3D printing of alumina
I want to print a structure of alumina, and the 3D printer that I am using is an extrusion-based printer. So I need your help in knowing that what composition (binders and deflocculant) of alumina ...
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4answers
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Where does the potential energy of capillary action come from?
Capillary action is when water pulls itself up a paper towel, glass tube or a tree. It is going up, which results in an increase in potential energy. According to the law of conversation of energy, ...
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1answer
195 views
Adhesion of polymerized fats to cast iron
I'm trying to make an informed decision as to which oil is best to use for cast iron seasoning. I've read all kinds of conflicting information online and the only consistency seems to be that ...
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1answer
53 views
Why does the surface of an acid appear to have a stronger “dissolving power”?
In this Periodic Videos YouTube video by Brady Haran and the University of Nottingham, we see a piece of gold being dissolved in aqua regia, while Professor Poliakoff explains why aqua regia can ...
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Why are lyophillic sols uncharged and lyophobic sols charged?
Gums, resins, glue, gelatin starch are uncharged and lyophillic where as metal sulphides and hydroxides are charged and lyophobic.
Right after studying o-chem this seemed quite contradictory as ...
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1answer
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How does critical temperature affect adsorption?
I don't really understand how does a high critical temperature favour adsorption?
What I think is that the lower the temperature, more easy is it for the gas to liquefy and therefore adsorption is ...
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1answer
2k views
Why do bubbles form on the side of a plastic bottle?
I have a plastic bottle filled with drinking water where only one side of the bottle has air bubbles. I know that water is not pure and there are dissolved gases, and my theory is that there are small ...
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1answer
90 views
How can I make an alloy wetter?
I'm trying to make a Bismuth-Indium based low-melt alloy wetter (specifically, better at wetting to solid metals and glass). I've tried adding gallium, which obviously works, but due to its metal-...
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229 views
What is the effect of temperature changes on rate of chemisorption?
In chemisorption, if temperature increases, then after some time why does its rate decrease? I tried to explain it by Le Chatelier's principle but I don't believe it's valid as chemisorption is ...
