# Tag Info

26

It boils down to the definition of soap. Wikipedia defines a soap as the salt of a fatty acid. IUPAC claims the smallest fatty acid can be considered to have 4 carbons. Therefore the simplest soap molecule would be a (generally sodium) salt of butyric (butanoic) acid, i.e. sodium butyrate. Now apart from the chemical definition, a soap must adhere to its ...

18

Quoting a reddit post from chemist nallen: The short answer is that the dirt and oils from your hair compete for the surfactants making them less available to form lather, which is small bubbles. To better understand the mode of action, you have to know a bit about the formulation of shampoos and the nature of dirt and oils. Dirts and oils deposit on hair ...

16

(My sister-in-law works at Unilever, and she makes these soaps) These are all detergents. The primary differences are harshness (hand soaps can be harsher, as hands are often more soiled), lathering, concentration, perfuming/scents, and marketing. (Emphasis on the marketing.)

14

The froth has little or no effect on the detergent action. In fact detergent manufacturers have to add anti-foaming agents to stop excessive foam generation in automatic washing machines. Froth/foam is generated because surfactants in the detergent adsorb at the air water interface and stop the water film that makes up the walls of the bubbles from ...

13

I don't remember to have seen the term tensid outside the context of the German language. The term is typically applied to agents that decrease the surface tension (hence tensid) of water. Note that the logic behind the English equivalent surfactant is just the same. So, in summary tensid and surfactant mean the same.

11

The simplest kinds of soap are just a fatty acid chain with something more ionic on the end - something like the ubiquitous sodium laureth sulphate: When it's in bar form, it behaves a bit like a solid block of plastic, because chemically speaking, those long chains of carbon are quite a lot like a common plastic such as polythene. These chains attract ...

11

The color of the precipitate is strongly reminiscent of copper(II) hydroxide. I hypothesize: Chloride corrosion of copper from exposed brass (ref 1 || ref 2) a. Per ref 2 above, sulfate may also participate Alkaline precipitation of $\ce{Cu(OH)2}$ in the neutrally-buffered soap Insufficient $\ce{Na_4EDTA}$ to complex the amount of $\ce{Cu}$ corroded from ...

10

According to the MSDS for Jet Dry (a common brand name) it contains: Sodium 2-phenylpropane-2-sulfonate (Sodium cumene sulfonate) Propane-1,2-diol Citric acid I think it may be safe to assume that the citric acid is in there for a "clean" smell and also to soften the water (thanks to the commenter). The sulfonate is presumably a surfactant to help break ...

8

It's a bit of a blunt instrument, but I'd tend to just go straight for hydrogen peroxide if it's available where you are. It breaks up all sorts of organic dyes via oxidation, and it slowly decomposes by itself, especially in sunlight, so you can just rinse (thoroughly) and leave it to dry in the sun. (NB: I have never owned a wine decanter, and take no ...

8

Briefly, the cause for surface tension is the difference in the energetic state between a molecule at the surface compared to a molecule inside the liquid phase: the molecule inside has lower energetic state as it has more inermolecular interactions (or, to get to the surface, a molecule needs to break intermolecular bonds, which needs energy). This is more ...

7

While I agree that the definition matters I disagree with the definition of soap as "as the salt of a fatty acid". For one SDBS, AOT, SDS, Cocamide DEA (not even a salt) and CTAB are all popular soaps that are not fatty acid salts. I also do not think that soap and surfactant are interchangeable words. Surfactants lower surface tension, soaps create micelles ...

6

Yes, this is a good explanation. Rain water is almost pure water, it lacks of bivalent ions such as $\ce{Ca^{2+}}$ and $\ce{Mg^{2+}}$ which helps soap to rinse of. You will get the same effect when a water softener is installed on water distribution.

6

Volatile surfactants There are many molecules that are both surfactants (in water) and volatile, but of the ones I can think of, none can be used safely in home laundry applications. Hydrocarbon derivatives. The examples you found by googling are in this class. 3,5-dimethyl-1-hexyn-3-ol is the principal component of Surfynol 61 (probably named Surfynol ...

6

I am wondering if there are surfactants that exist in a gas state that can be used to reduce the surface tension of a liquid. The most direct answer is "no". Gases do not have surface tension and gas-phase molecules do not chemically affect the surface tension of liquids. I know its a broad question, so for example, are there any gases that could reduce ...

5

SLS is highly soluble in water (100g/L) Therefore, in the specific case of your teeth having lots of bubbles around them after brushing, you should simply gargle your mouth with water to remove the excess SLS.

5

Your goal is to reduce the surface tension of the water so that it does not support the formation of large bubbles or inhibit the whetting of the dirt particles. When the bubbles are small, the dust inside will be more likely to make contact with the liquid surface of the bubble within the lifetime of the bubble. Also, when it does make contact, it will ...

4

Borax was used as a "builder" in washing formulations long before perborate was used as a bleach. "Builder" is the terminology for additives which reduce the influence of water hardness. Other examples of builders include trisodium phosphate, soda, polyphosphates (like Graham's salt) or today most often aluminosilicate ion exchangers (Phosphates are more or ...

4

The micellization releases water molecules which initially solvate the hydrophilic head groups. The release of these waters greatly increases the entropy. Reference: Dong et al., Chem. Rev. 2010, 110, 4978-5022.

4

The most likely cause of a "soapy" taste and sudsing from filtered water is a reverse osmosis filter, for which the usual membrane preservative used to keep the filter from degrading before its first use is plain old glycerin, a common ingredient in and byproduct of traditional soap (though most cleansing products nowadays, even those marketed as soaps, are ...

4

Tap water contains calcium and magnesium ions; more so if the water is hard. These ions can bind to soap over time and make an insoluble soap curd. Is the sponge clean? If not, another reason is that the surfactants in the soap that make the foam might be forming micelles around whatever grime is in your sponge, so that there aren't many left to make the ...

4

There's no technical reason why you couldn't make a powdered dishwashing detergent and I suspect that someone probably does sell it, just as there are liquid, tablet, and powdered automatic dishwasher detergents and laundry detergents. It does seem more convenient to use a liquid detergent for washing dishes in the sink. A liquid doesn't need time to ...

4

CTAB, aka Hexadecyltrimethylammonium bromide DTAB, aka Dodecyltrimethylammonium bromide Sort of a vague question, don't know where to start. To begin, CTAB has a hydrocarbon chain length of 16 (as its name suggests) whereas DTAB has a -CH2- chain length of 12. Otherwise they have the same hydrophilic/polar "head"; all this is obvious, you can tell just by ...

4

I'm afraid no: you are applying a chemical principle to a complex biological response. The Le Chatelier principle state: If a chemical system at equilibrium experiences a change in concentration, temperature, volume, or partial pressure, then the equilibrium shifts to counteract the imposed change and a new equilibrium is established. We start with the ...

4

I don't have a lot of experience with salicylic acid as I'm just starting to work with it myself at the moment. However, I find that it disperses better if it is added to the solution at a high temperature (before surfactants) and then homogenised (once thickening agents, if any, have been added). The other thing which may help is by dissolving in denatured ...

4

Cationic micelles similar to your examples can and do exist. For example cetyl trimethylammonium bromide (Growth of Cationic Micelles in the Presence of Organic Additives, P. A. Hassan and J. V. Yakhmi, Langmuir, 2000, 16 (18), pp 7187–7191, DOI: 10.1021/la000517o). Additionally, there are cationic micelle detergents (Ionization of cationic micelles: ...

3

Can I wash my hair with dishwashing agent [...]! If it's an agent for dishwashing machines: Please DON'T! Cleaning in dishwashing machines is performed in alkaline medium. The tabs usually contain (among others): alkaline compounds, such as sodium carbonate and sodium hydroxide bleaching agents, such as sodium perborate and sodium percarbonate ...

3

After quick digging I found, that glass cleaner solutions usually contain alcohols and surfactants. This additions reduce surface tension and allows the solution to interact with glass more easily, distributing the solution over the entire surface. The white stripes visible after water dried are usually solid salts. If the water does not contain any salts, ...

3

While this question should get a more elaborate answer, mine will at least give you leads. Soaps act as surfactants, that is, they are amphiphilic (both hydrophobic and hydrophilic) molecules that lower the surface tension of a liquid. By lowering the surface tension of water, soap bubbles can form, the surface becoming more "elastic" - the molecules at ...

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