Recent content by pisluca99

Generally, a bathochromic shift is observed when there is conjugation between more chromophore groups, that is, an increase in the absorption lambda max is observed. But what lambda max is being referred to? For example, comparing ethene and butadiene there is a batochromic shift only if we...

And that is clear. But, for example, considering an electric discharge that excites hydrogen atoms, should it not "possess" a single energy value, corresponding to the ∆V between the electrodes? For example, there is a ∆V of 200 V between the electrodes, which generates a discharge that has an...

By exciting hydrogen vapors with heat or electrical discharges, it is possible to obtain the element's emission spectrum. In it, as can be seen, appear multiple wavelengths, each corresponding to a particular orbital electronic transition. From this it can, therefore, be inferred that heat and...

In spectroscopy, the highest peaks in the absorption spectrum are those that are associated with the most probable energy transitions in a molecule. The most probable transitions are those in which the best superposition between the wave function of the vibronic level of the fundamental state...

So essentially, every wavelength is absorbed, reflected and transmitted to some extent. For example, in the case of benzene, it does not absorb at all (or at least extremely little) between 400 and 700 nm, so all this radiation is largely transmitted and to a smaller extent reflected. Since...

Essentially because I wanted to highlight the fact that the absence of color is due not only to the fact that benzene transmits all visible radiation, but also because our eye cannot perceive the UV radiation that is reflected (or transmitted ?? This is another doubt I would like to clarify) by...

I was trying to understand why some compounds appear colorless (transparent) and tried to give an explanation. I take benzene as an example: it is a chromophore group in which there is π-conjugation, so a certain energy gap is generated between HOMO and LUMO. This energy gap is such that in...

Ok, thanks for your time!

Oh perfect. But then how do you explain that polar/strongly polar molecules, therefore with a high dielectric constant, dissolve in water? They must necessarily form many hydrogen bonds. So there must be a sort of relationship between dielectric constant and hydrogen bonds..

Ok thanks! Still referring to the concept of solubility, is there a relationship between the dielectric constant and the magnitude of hydrogen bonds? For example: water has a high dielectric constant, so it is a strongly polar solvent, so it will dissolve equally strongly polar solutes (i.e...

Two substances are known to be miscible when the intermolecular interactions formed between the molecules of one substance are equal to those formed between the molecules of the other substance. That said, why is benzoic acid, which is predominantly apolar, so it mainly forms London...

We can find concentrations with ICE method. So you mean that It Is useless to exploit H-H if we can find all with ICE. It makes sense. What do you mean? What i mean Is that, when the reaction between acetic acid and NaOH happens, the solution will have a certain final pH. Using this pH we can...

Therefore, since the H-H is a simple rearrangement of the Ka, everything that can be evaluated with the ICE method will have to coincide with the H-H itself. Therefore, the concentrations [CH3COO-] and [CH3COOH] which are found with the ICE method, at the end of the reaction with NaOH, can also...

From the concentration we can find the starting pH of the solution (basic), then, with the H-H we can find relative quantities of CH3COO- and CH3COOH: log ([CH3COO-]/[CH3COOH]) = pH - pKa , so [CH3COO-]/[CH3COOH] = 10^(pH-pKa) = ā. Then the degree of dissociation DD = ā/(1+ā). The problem is...

Sure, we can reach the H-H equation starting from Ka. Usually It Is used for buffered solution, for example to evaluate the pH of a buffer, but also to evaluate the degree of dissociation of an ionisable compound. However, I don't understand if the degree of dissociation can be evaluated only in...