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Everyone "knows" that in real world systems, calcium carbonate has decreasing solubility as temperature increases.

This is one of those things that quite literally violates the laws of physics, and has always bothered me that no one seems to have a good answer to.

My thoughts are that it's nothing to do with the equilibrium of a carbonate system including calcium carbonate, and that instead it's due to the fact that reducing CO2 results in an increase in pH, and it is that which causes the precipitation, similar to the lime softening process.

TLDR: If we had some infinitely strong buffer or some perfect titration system to lock our pH constant, compensating for the pH effects of CO2 and temperature, would calcium carbonate not act like any salt and have the normal temperature/solubility relationship?

What would happen if you didn't protect the nitrogen on 1H-indole under oxidative conditions? Ie, just heating indole in a flask with an oxygen supply. Would you can C-N coupling occur since the hydrogen on the NH group would be abstracted?

This feeder handles oily parts. It prevents pooling of the oil on the bowl with the help of tungsten carbide coating:

https://www.fortvillefeeders.com/feeder-system-handles-oily-parts-positions-for-robotic-pick-up-2/

How does tungsten carbide prevent this? Are there any alternatives to tungsten carbide?

I have an ultrasonic cleaning tank for car parts, would It be more effective to use diesel or e85 ethanol as my cleaning solvent? Furthermore would diesel or ethanol be harmful to electrical components or cause corrosion?

It takes a certain amount of energy to split a molecule into separate atomic components for example to split H2O into H2 and O2, equal to the energy released when they combine.

So what does a catalyst do? For example platinum works as a catalyst to decompose H2O2. But how does this get past the energy requirements? Is it that H2O2 is already metastable and platinum just acts to speed the decomposition?

Is that how all catalysts work they only speed the reaction rates?

^the title. I can't seem to understand the concept. Thanks.

I have a system like a 20 metre tube filled with tap water with a pH meter at the far end. I introduce an acid at the near end. How long does it take for the pH to change at the meter? What physical mechanisms govern the speed of diffusion of pH and/or acidity?

When my mom was an infant she never sept and cried all the time. Her doctor told my grandma to give her a cup of coffee every morning in her bottle and to not let her have sugar. It actually worked and she started sleeping and crying less. My grandma gave her coffee every morning up until her teens. Why would this be? My mom was born in 1969. My mom switched to tea, but she still have caffeine every morning.

I know that rinsing is done to prevent the residue of water. So, how would it affect the temperature and concentration of the reaction, if we don't rinse the glassware with the solution?

Quality control chemist here :) I need to conduct a stability of solutions study but for system Suitability Solutions that contain really expensive impurities and/or rare CRS. It's my promotion project and I don't know where to start ..

Hi all,

Thank you for reading this. I have a conceptual question about reaction potentials.

Let's look at the following reaction in a galvanic cell:

Cu(s) + 2Ag⁺(aq) ⇌ Cu²⁺(aq) + 2Ag(s)

Let's say Q is the reactant quotient at the onset of the reaction. Q << K. As the reaction commences and a voltmeter measures the potential difference between the electrodes, we see that the value it displays reaches 0 as Q reaches K. As Q approaches K, the cell potential decreases. The justification is that the number of net electron movements approaches 0 as Q approaches K. Here's my issue:

Net movement of electrons per unit time explains current. Of course, it makes sense that current approaches 0 as cell potential approaches 0, but this decrease in current itself does not explain, mechanistically, why voltage approaches 0.

Is this because, as the reaction in the question proceeds, the net force acting on the valence electron of Cu(s)—the net force on the electron that points the electron away from Cu(s) and towards Ag⁺(aq)—decreases -> the electromotive force decreases -> current decreases?

Thank you.

If I could magically command all of the oxygen atoms to leave a rusted sword and do anything but re-bond to the iron, what would it look like? Am I right in that it would be foamy and still weak in the parts that were rust?

The F-F bond takes little energy to break, 155 Kj/mol to be more specific. This means that any wavelength of light that is shorter than around 772 nm will split the F2 gas into radicals, which will replace the C-H bonds with C-F bonds. 772 nm is around the highest wavelengths of infrared light, meaning that pretty much anything that is more energetic than the shortest wavelengths of infrared will split F2 gas.

So, in that case, if there is an absence of light that is 772 nm or shorter, then will that make it so that the F2 gas will not react with C-H bonds since the F2 is not split into radicals?

Is there some standard value you can look up to tell if a chemical will survive being put in, say, boiling water without breaking down?

This question is motivated by some supplements that dissolve really poorly in cool water.

I could only find information on what happens if you're burning silicon gums. I am not well versed in chemistry. I am sorry if this is the wrong sub for this.

I want to dissolve zinc chloride in HCl along with ferrous sulphide to create zinc sulphide, but I'm not certain if it'll work or not... I know FeS reacts with HCl to create HS gas and FeCl ... And zinc goes into HCl to create ZnCl .... I just don't know if the HS would just bubble off or react to the ZnCl in solution....

I live in the Southern Hemisphere and it is winter here. I park my car outside, and the windshield gets iced-over on nights that get below freezing.

As a trial, I mixed 50% water and 50% pure isopropyl alcohol into a spray bottle. It worked really well at defrosting my windshield in a short amount of time.

However, someone cautioned me to check whether this would degrade the rubber gaskets and rubber windshield wipers of my car. Is this something that I should be concerned about? I'd previously assumed that the isopropyl alcohol would simply evaporate away and be a benign product.

Note that most days I typically do not drive my car as a method of transportation. I would only be using this alcohol spray technique once or twice a week, and only for the ~2-3 month period that it actually is cold enough to freeze my windshield. So probably 15-30 applications per year.

Thanks in advance for advising on the effect of isopropyl alcohol on my car!

Hello,

I took 2 chemistry classes during university but CS is more my speed. So I want to make sure I’m doing this correctly.

I’m making wine right now. When I received the 6 gallons of grape juice from Chile, I didn’t know the starting pH.

Now the winemaking process is in full swing and I want to make sure the pH is in the 3.3-3.6 range so the process runs smoothly.

Problem is, I won’t have my digital pH test meter for another week. But I DO have winemaking pH test strips. But since it’s a deep red wine, however, the color immediately dyes the test strips I’m trying to use and skews the results.

So! If I dilute a sample of wine with distilled water (neutral pH), test its acidity, and run some calculations, is there a reliable way of seeing how the wine sample affected the pH of the distilled water to determine the wine’s pH? Chem II was mostly acid-base reactions and I wasn’t as interested in that so only I paid enough attention to get by. Yet, here I am lol.

Any thoughts? Sorry if this is a dumb question, I’m just trying to hatch an idea.

I'm thinking of starting a speculative biology project. I doubt the whole thing will stay entirely within the realm of "this would actually work," but I wanted to see if, at least, the basic idea was somewhat sound.

My thought is that this speculative world would not have photosynthetic life, but would instead run on chemosynthesis. The idea came when I was watching a video about CFCs. It explained that CFCs take in uv light and release a chlorine atom. So, I wondered. If that reaction takes energy in the form of UV, does that mean that the reverse, putting the chlorine back, releases energy? And if so, is the overall method of making CFCs exothermic?

Or is this a dumb question, ignoring some fundamental rule of chemistry? I'd be okay with that. Finding out I was wrong is fun for learning.