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Questions tagged [colloids]

A colloid is a substance in which microscopically dispersed insoluble particles are suspended throughout another substance.

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4 votes
2 answers
389 views

Weirdness From Boiling Gold Colloid Dry

I was doing an experiment in my chemistry class and found something odd. We prepared a colloid of gold with the following procedure. 1: Measure out 20ml of Hydrogen Tetrachloroaurate (iii) in grad ...
3 votes
2 answers
3k views

Separating Lipids from Milk

I am trying to develop a procedure to test the percent mass of lipids in (update: homogenized) milk. It doesn't need to be very accurate, just an interesting application of chemical principles. As I ...
-4 votes
0 answers
37 views

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 ...
2 votes
0 answers
55 views

Temperature and zeta potential

What is the temperature effect on zeta potential? My problem was assigned by my teacher for the final exam preparation: "When the temperature is increased, and given in this temperature range, ...
1 vote
1 answer
27 views

Co(NO3)2 forming colloid in H2O, and Methanol

I was just trying to make a stock solution of some Co(NO3)2 . One in H2O, another in Methanol. Both don't completely dissolve. They're almost dissolved and appear near translucent but when shining a ...
3 votes
0 answers
181 views

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 ...
0 votes
0 answers
156 views

Why is micelle formation endothermic?

Most websites mention that it is endothermic and some mention that it is endothermic at low temp. and exothermic at high temp. Nor do I know the correct answer neither I can guess the reason for any ...
1 vote
1 answer
3k views

Why is gold sol used for intra-muscular injection?

In my textbook it is written that gold sol is used for intramuscular injection. But, actually what is its use? Why would people use such a precious element for injection. Can other colloids be used ...
7 votes
3 answers
17k views

The entropy change during micellization

I was reviewing the thermodynamics of micelle formation from the Wikipedia page and this book. I understood most of the arguments but micellization is supposed to be an entropy driven process with a ...
2 votes
1 answer
50 views

Watercolor pigment conundrum - can a change in ionic profile induce flocculation?

A client of mine has installed an ion exchange water purifier to de-harden her tap water. After that, however, she noticed that it has negatively affected her watercolor painting. From what she ...
5 votes
1 answer
559 views

Charge acquired by sols after their preparation

This table from my textbook (p. 20), shows nature of charge on particles of listed sols, in their original or natural form. What reasons can be attributed to oxides (sols) being positively charged? ...
1 vote
1 answer
90 views

How do clay particles form a colloidal mixture?

I have been learning about water coagulation in my chemistry textbook. Apparently, before being treated, water has clay particles, primarily silicates and aluminosilicates, which apparently have a ...
2 votes
2 answers
411 views

What kind of solution is formed when alkali metals are dissolved at high concentration in liquid ammonia?

When an alkali metal is dissolved in liquid ammonia, it results in the formation of a deep blue coloured solution. $$\ce{M + (x + y) NH3 -> M+(NH3)_x + e^-(NH3)_y}$$ The ammoniated electrons absorb ...
0 votes
2 answers
536 views

Why can't there be a gas-dispersed-in-gas colloid? [closed]

Colloids, a special type of heterogeneous mixtures, typically have two components. One is the dispersed phase (DP), which is the "solute-like" part and another one is the dispersion medium (...
5 votes
2 answers
799 views

Name of particles in a suspension

What is the proper name given to the particles in a suspension? Suspensae perhaps? When these particles are brought out of suspension, and precipitate down to the bottom of the mixture, what is that ...
-1 votes
2 answers
565 views

Generating colloids / nano-particles from palladium and platinum wire

I know I can generate colloidal silver from the following link generate colloidal silver I now have 2 palladium and 2 platinum wires and would like to make one colloidal solution of palladium and one ...
1 vote
1 answer
2k views

DLVO Theory of Colloid Stability

DLVO theory gives the curve of potential energy vs distance of two colloid particles. Potential energy curve is derived for colloids being only electrostatically stabilized and not sterically. Looking ...
2 votes
0 answers
51 views

Why do silver halide crystals in suspension, develop a surface charge

This is a question related to analog photography. Photographic films have a suspension of silver halide crystals in them, and these crystals have adsorptive properties which are used in this ...
5 votes
1 answer
156 views

Bond-order parameter $g_6(r)$

I would like to know the explicit steps to compute the bond correlation function $$g_6(r) = \langle\Psi_6^*(0) \cdot \Psi_6(r)\rangle$$ for colloids in my experiment (2D). I have the position of all ...
1 vote
0 answers
19 views

Will a liquid-liquid emulsion and the separated emulsion have same volume?

Let's assume that there is no dispersed gas (bubbles). Not sure about dissolved gas; maybe you can tell me if that matters. Ordinary liquids (aqueous solution and biological oil). Surfactants are ...
0 votes
0 answers
31 views

What allows for colloidal solutions of polymers to act like solutions despite the large size of polymers?

I have been introduced to a paragraph in my textbook that I am trying to understand. Macromolecular colloids: Macromolecules in suitable solvents form solutions in which the size of the ...
2 votes
0 answers
376 views

Why are colloidal sol particles of acidic dyes negatively charged and basic dyes positively charged, when it should be the other way round?

From NCERT Class 12 Chemistry; Sri Aurobindo Marg, New Delhi, India; January 2019; p. 136: Colloidal solutions of basic dyes like methylene blue are positively charged whereas colloidal solutions of ...
6 votes
0 answers
420 views

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 ...
2 votes
2 answers
784 views

How does adding HCl convert AgCl into a sol?

According to the text I follow, in peptization the ions of the added electrolyte (peptizing agent) get adsorbed by the particles of the precipitate and turn the precipitate into a sol. An example of ...
1 vote
0 answers
31 views

Brownian motion of asymmetric particles

The classic Stokes-Einstein relation ($D=k_BT/(6\pi\eta r)$) it is assumed that the particle undergoing Brownian motion is spherical, and experiences ordinary Stokes flow between (or during) ...
2 votes
0 answers
28 views

How practically to determine dispersion's Hamaker constant using CCC?

I know that Hamaker constants can be determined from CCC data. $$ccc=\frac{9.85 \cdot 10^4 \epsilon^3 k_B^5 T^5 \gamma^4}{N_A e^6 A^2 Z^6}$$ Where, $\epsilon$ is solvent dielectric constant, $N_A$ is ...
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 ...
4 votes
1 answer
229 views

How to prevent sedimentation of an EDTA suspension?

I tried to create a suspension of EDTA powder in glycerin with 1:1 ratio. I keep facing problem of EDTA sedimentation. I've tried other ratios also but this was the only one which formed least amount ...
0 votes
0 answers
42 views

Particle tracking in colloids and uniformity in fractional part function

I don't know if its right place to ask this question since chemistry and programming both are involved. I was working on particle tracking of series of pictures (.tiff) of colloids. And I was Using ...
1 vote
0 answers
39 views

When is it realistic to model diffusion without advection?

Brownian motion abounds in nature, but so does drift current. In theoretical models of solutions and colloidal suspensions it is sometimes assumed that advection is negligible. I'm wondering if this ...
5 votes
2 answers
78 views

Why are nanoliposome encapsulated antibiotics still so unavailable despite being so effective?

I wasnt sure how the phrase the headline question really nor if this is the right place to ask it, but i'm primarily interested in the chemical synthesis aspect and the experience of chemists ...
1 vote
1 answer
2k views

Are the particles of a colloid "solid"?

I want to understand what are the particles of a colloid in the microscopic scale. According to Wikipedia: A colloid is a phase separated mixture in which one substance of microscopically dispersed ...
1 vote
1 answer
707 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....
2 votes
1 answer
1k views

How do I create a transparent liquid for ferrofluid display?

Hello~ I am a media art artists working in Korea. Recently, create a kinetic artwork using ferrofluid. I need to create an artificial pond with a diameter of 3 meters. So I need a lot of suspension ...
1 vote
0 answers
25 views

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 ...
0 votes
1 answer
70 views

Actual color of colloids [closed]

I have read that the color of colloid depends upon the wavelength of light scattered by the dispersed phase and also in the sense in which the receiver receives the light. If all of this depends on ...
1 vote
2 answers
137 views

Water purification procedure that does not involve a flocculant of any kind?

I have read about "electroflocculation" that uses less flocculant/alum, but is there a method – no matter how expensive or impractical – that uses no flocculant at all?
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1k views

Boilling colloidal silver?

I have some colloidal silver that i bought from a shop. It is 18ppm, however, I need a higher PPM and I can't seem to buy it anywhere where I live. If I boil this colloidal silver, would it make the ...
1 vote
0 answers
34 views

How does total depth affect the colloid gradient?

When a colloid reaches diffusion–sedimentation equilibrium, it creates a gradient where the solute concentrates toward the surface or the bottom of the vessel based on its density relative to the ...
0 votes
3 answers
638 views

Colligative properties of colloids [closed]

The following lines are from my textbook: Colloidal particles being bigger aggregates, the number of particles in a colloidal solution is smaller than a true solution. Hence, the values of ...
2 votes
1 answer
561 views

Why does a low concentration of soap in water behave as a strong electrolytes?

According to my text, "a colloid in which the dispersed phase consists of micelles is called an association colloid." An example would be soap in water. They use the term 'associated colloid' and '...
3 votes
2 answers
64k views

How can I get a hand sanitizer solution to form a gel?

I am trying to formulate a gel hand sanitizer for a thesis project. The sanitizer that I have right now is watery and will not gel. My teacher told me to change our formulation because it is not good....
0 votes
1 answer
1k views

Why does Tyndall scaterring produce conical shape?

When light is passed through a collidal solution, due to Tyndall scattering, the path of light appears to be a bright cone. Why does it have to form only a conical shape? The conditions for Tyndall ...
2 votes
0 answers
75 views

hydrodynamic thickness of polymer vs. concentration of electrolyte?

I've measured the hydrodynamic thickness of a NaPSS layer on polystyrene latex and plotted it against the concentration of the supporting electrolyte, NaCl. My graph shows a general decrease in ...
2 votes
0 answers
218 views

Estimating maximum size of magnetite particles in this Nile Red ferrofluid video?

In the Nile Red video Making ferrofluid from scratch a suspension of small magnetite ($\ce{Fe^{2+}Fe_2^{3+}O_4^{2−}}$) particles is produced from a combination of ferrous chloride and ferric chloride. ...
1 vote
1 answer
2k 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 ...
0 votes
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182 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 ...
1 vote
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82 views

Gelifying hydrogen peroxide

What substances could be used to gelify 60% hydrogen peroxide? I imagine anything organic like agar would be broken down by the radicals. I tried looking up what dentists use and the only thing that ...
0 votes
1 answer
123 views

Is it possible to make micelles to pick up Microplastics from water?

I'd like to know if I could get micelles to pick up microplastics in water. I read that microplastics are sometimes charged, so can we make the lyophobic end to pick up microplastics, so that they can ...
2 votes
0 answers
104 views

How to charge titanium dioxide particles for a DIY e-paper capsule? [closed]

I'm trying to make a single e-paper capsule (1 cm × 1 cm) at home. At first, I tried to charge the $\ce{TiO2}$ particles by putting them in $\ce{H2O}$ with $\ce{NaOH}$ and then putting that whole ...