Questions tagged [absorption]

In chemistry, absorption is a physical or chemical phenomenon or a process in which atoms, molecules or ions enter some bulk phase – gas, liquid or solid material.

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Will charcoal briquettes (not activated) absorb water out of the air in the house in a subtropical climate?

I live in Florida, an incredibly wet environment where it's very difficult to get moisture out of house without using a dehumidifier 24/7, which is too expensive. Would charcoal briquettes be of any ...
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Are there chemicals that absorb and release upon heating oxygen more efficiently than potassium oxide?

$\ce{K2O}$ absorbs oxygen forming $\ce{K2O2},$ which decomposes to $\ce{K2O}$ and $\ce{O2}$ at 500 °C. This means that $\ce{K2O}$ can absorb up to 17% its mass of oxygen. Are there other substances ...
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What fraction of the vapour in electronic cigarettes is water?

Not a chemist but looking for an answer I can understand. Electronic cigarettes use propylene glycol and/or vegetable glycerin as a base liquid. This is heated and vaporized at a low temperature (my ...
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Using table salt as a way to limit humidity in an unoccupied house

We own a static caravan in the UK (Snowdonia region, so rainy and wet all year round, moderately cold winters) and we leave it unoccupied during Winter (Oct-Feb). We were advised of an apparently ...
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How is Mn+7 in the Permanganate ion considered as momentarily reduced to +6 in LMCT? [duplicate]

I saw this passage on a book and it says that Ligand to Metal Charge Transfer (LMCT) overpowers d-d transitions thus the permanganate ion has an intense purple color. However, it was mentioned that ...
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Is the water absorbed by sodium polyacrylate available to react?

I'm curious whether the water absorbed by sodium polyacrylate would react with alkali metals, or be trapped by the sodium polyacrylate.
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tolerable error, CASSCF simulation of UV/Vis spectrum

Please forgive my ignorance of experimental spectroscopy. I am a computational chemist, not an experimental one. My question is: what would be considered a tolerable or reasonable difference between ...
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When making a calibration curve, do we have to use the wavelength at maximum absorbance?

If you are making a calibration curve for $\ce{CuSO4}$ where you plot absorbance against concentration, does the wavelength have to be exactly at the maximum of the peak? Or can it be somewhere else ...
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Vibronic coupling: How do I determine the new point group after vibration?

So I was recently discussing the transitions in Egyptian Blue ($\ce{CaCu[Si4O10]}$) with some of my students, who had to prepare this compound. What I like in particular in this case is how, at least ...
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What substance consumes oxygen from atmospheric air [closed]

I'd like to find an economical substance that will consume oxygen from a container. Steel wool comes to mind but I don't have an intuition how feasible it would be. The chamber is 5 gallons in size ...
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Effective attenuation coefficient for polychromatic light

The Beer-Lambert law gives the optical intensity of collimated light as a function of depth $z$ as: $$I(z)=I_{0}\mathrm e^{-\gamma z},$$ where $\gamma = \alpha + \beta$ is the wavelength-dependent ...
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Hygroscopic Substances and Drying Agents

My book says: Most of the hygroscopic substances are drying agents Based on what I read on several websites, I think dehydrating agents also act as drying agents. If so, all dehydrating agents ...
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What kind of drugs can be absorbed through skin? [closed]

Some drugs such as nicotine can be administered through skin. I thought the layers of skin are designed to prevent in-flow of any chemical/germs. Not all drugs get absorbed in this fashion. So do ...
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What is the relationship between emission and fluorescence?

A molecule exposed to a photon with some energy is put into an excited state, and emits a photon of some energy when it returns to ground state. The photon that provided the energy for excitation ...
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Calculation of silver nanoparticle size using Mie Theory

I have synthesized silver nano-particles and I wish to determine the approximate particle size using the wavelength that was most absorbed according to its absorption spectrum. I find out that Mie ...
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How much water vapour can a gram of Uppsalite absorb at NTP?

This site states: It turned out that Upsalite had the highest surface area measured for an alkali earth metal carbonate; 800 square meters per gram. Assuming that a sphere may enclose the maximum ...
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What is the difference between dissolution and absorption?

Let us first look at the definitions from Gold Book: Absorption: The process of one material (absorbate) being retained by another (absorbent); this may be the physical solution of a gas, liquid, ...
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Improving efficiency of absorption refrigerator (ammonia+hydrogen)

Apologies if this is not the right forum for this question, I checked the Physics side and there's no questions on this, whereas there's at least one other question here about absorption refrigeration....
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is the adsorption of resveratrol within wine or grapes linked with the time it was kept in your mouth?

This question is about resveratrol in wine or grapes and not in some special delivery system. If one is drinking some wine or eating grapes, does it matter if they keep it in their mouth a bit so the ...
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Explaining color differences using bond conjugation

I'd like to ask about how the color differences between the dyes methyl violet and malachite green can be explained. Looking at the conjugated bonds of each, methyl violet seems to be more conjugated ...
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Finding the wavelength of maximum absorption of Tartrazine using Fieser-Kuhn

How would you use Fieser-Kuhn rules to calculate the wavelength of maximum absorption for tartrazine? Fieser-Kuhn rules states that: $\lambda_{max}=114+5M+n(48-1.7n)-16.5\ R_{endo} - 10\ R_{exo}$ ...
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Would silica have the same effect as activated charcoal?

Silica found in "do-not-eat" packets is a desiccant (I'm not sure about this); and so is activated charcoal. Would consuming it have the same effect if one were to have a stomach ache?
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Determining the calcium content in cashews via titration?

I have been planning on an experiment for quite some time now (as part of my after-school chemistry club), but I still feel like I am missing something. Due to my family's calcium deficiency, I ...
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Why does my absorbance change over time?

I have a solution of black phosphorus quantum dots suspended in water that I prepared by sonicating black phosphorus powder in n-methyl-2-pyrrolidone and centrifuging to isolate the quantum dots. ...
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If polyethylene glycol (PEG) is hygroscopic, how does it protect wood?

Archaeologists and conservators use polyethylene glycol (PEG) to replace water inside wood to protect it from shrinking and expanding with changes in humidity. But it is hygroscopic—even more so than ...
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Rate equation for a reaction involving a polymer having absorbed small proteins according to langmuir's model

First, let me apologize for the awful question title.. I have a solution with polymers with $N$ binding sites and small proteins, which can attach to a binding site. The polymers will absorb the ...
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Resonance condition for absorption of energy

In NMR, for example, why it is not possible to excite nuclei from one spin state to another using energy of arbitrary frequency?
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Would adding water to a fish tank with sand lower the level of sand?

Let's say I have a typical 10 gallon tank with dimensions 10" x 20" x 12", and it's filled halfway (5" in height) with dry sand for hermit crabs. If I fill the tank up with water, will the level of ...
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Relative strength of desiccants

Is it meaningful to characterize the relative strength of desiccants? For example, is there a measure of hygroscopy, or an ordering of desiccants, such that higher ones will always dry lower ones? ...
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Look for superabsorbent balls whose expansion is reversible

I am glad to find very cheap superabsorbent balls (see image below). However, I found their expansion is not reversible. The wiki entry 'Superabsorbent polymer' also says that the material will '...
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Lipinski's Rule of 5 Oxygen Rules

I would like clarification on the role of oxygen as a hydrogen bond acceptor in Lipinski's Rule of 5 (for drug absorption). I have learned in my medicinal chemistry class that both electron pairs from ...
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Is UV-Vis absorption polarization dependent ? Why?

Consider molecule of interest be dissolved in a solvent (and this molecule has absorption in the visible region). We are using a broadband visible light source say tungsten lamp. This light passed ...
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What does activated carbon do to gasoline vapor?

What does activated carbon do to gasoline vapor? After the vapor is absorbed into a charcoal EVAP canister, what is left to be sent to the engine? My question is in reference to the work of Tom Ogle ...
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What chemicals could absorb/adsorb ambient atmospheric methane?

From an article in the New Scientist in 2010, Since pre-industrial times, methane levels in the atmosphere have risen from around 715 parts per billion to nearly 1800 ppb, claims Folberth. "If ...
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Absorption and ionization of rare earth ions

I'm studying silicate photosensitive glasses that contain $\ce{Ce}$ ions, and such glasses have an absorption band at 305 nm due to $\ce{Ce^3+}$. After that, the $\ce{Ce^3+}$ ion becomes $\ce{Ce^4+}$, ...
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Is there a way to liquefy a super absorbent polymer without using salt?

I understand that once a SAP absorbs a liquid it becomes a type of gel and that this gel can be liquefied by applying salt, are there other methods to liquefy this gel without using salt?
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What is the reason for the blue color of an ammoniated electron?

I am quoting a line from a book regarding reactivity of alkali metals with liquid ammonia. The blue colour of the solution is due to the ammoniated electron which absorbs energy in the visible ...
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Sulfur atomic absorption

Would the atomic absorption from FAA for Sulfur be from 3s2 -> 3p4 or 3p4 -> 4s0? I think according to the electronic partition function, there would be zero electrons in the 4s0 state at the ...
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What is the cause of hygroscopy?

Hygroscopy is the ability of a substance to attract and hold water molecules from the surrounding environment. Why are some compounds hygroscopic and others are not? What is it about their ...
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Spices are absorbed or adsorbed in food?

When we cook food, we add several spices and condiments which enhance color, taste and smell. Are these spices and condiments just adsorbed on the food particles? Or are they absorbed? For example ...
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Is there a visible change to baking soda when it reacts with odour?

For example, would a box of baking soda in a fridge lose weight as it absorbs odor? How long would it take to drop 100 g?
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Why is grease from cooking hard to remove from wood?

Cooking oil that jumps from a frying pan in use and over time accumulates around the frying pan on a wooden surface is sticky and hard to remove. My question is why. Why is it hard to remove? What is ...
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Removing harmful gases from automobile exhaust using electrostatic precipitation

If I attach an electrostatic precipitator to a car's exhaust - and also make the smoke pass through an area containing $\ce{NaOH}$ in order to absorb sulfur dioxide - does that mean that the smoke ...
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New finding in cobalt compound that absorbs oxygen - is it really a breakthrough?

Very recently Chemical Sciences published results of the discovery of a new cobalt compound that can absorb oxygen at presumably a higher capacity than what has been achievable before. The paper is ...