hypervalent_iodine

Can you show your attempts? 

Depends on the component I suppose, but HPLC or GC would be sufficient for a lot of organics. 

I am not a believer in any sort of deity (I was raised by two rather staunch atheists), but I have to ask why on earth one's religious affiliation (or lack thereof) should automatically preclude you from associating with them or accepting their advice? What sort of advice? Why would you not accept it if it appears to be well-reasoned and rational? 

On 2/22/2019 at 3:32 AM, swansont said:

Plastic Shoes has been banned as a sockpuppet account (probably The Operator and Taxonomist, and perhaps more, but definitely someone who has been here before)

Samatha Priss has been banned as yet another sock puppet of the above.

Jojowasaman, Hilary, Intothedarkagain, and Jojo_anderson have all been banned as sock puppets of one another, as well as being spammers.

What have you done so far / where are you stuck?

It’s just basic kinetics. Reactions occur when molecules collide at particular trajectories and with sufficient energy. If you have more molecules of a reactant around, you are more likely to get collisions more frequently and thus, the reaction occurs faster. 

The second step you have drawn out is incorrect. It should look like this:

As to why it occurs faster, think about what happens to the carbonyl carbon when the oxygen is attatched to when it becomes protonated. There are two resonance structures of the intermediate that forms, and it has a very big impact on the carbonyl carbon’s reactivity. The H+ you’ll notice is regenerated in the course of the reaction, which makes it a catalyst and is why we say it doesn’t formally participate in the reaction (since it isn’t consumed). 

What do you mean by work? 

1 hour ago, StringJunky said:

I had a look on Quora and it seems  it has middling electronegativity (2.2), so the atom it combines with determines which way it goes.

Yes, although it is worth noting that a hydride is, as far as I understand, more reactive (and thus less stable) than H⁺. You could not, for example, have something like NaH just sitting out in the atmosphere without it being protected in some way by paraffin or some such. As I said, I believe this due to electrostatic repulsion of the two electrons, and possibly something to do with nuclear charge.

Anyway, point being that as you and I have noted, hydrogen has the capacity to act as either a Group 1 or 7 element to some extent, and is kind of in its own special category within the periodic table. 

Technically, hydrogen can behave as either a halogen or an alkali metal, though it fits neither category completely and tends to be more of the latter. I would say one of main differences, and probably the most important one, between it and the halogens is in the fact that hydrogen only has an incomplete s orbital. This means that in its ground electronic configuration it only has 1 valence electron. Halogens have incomplete p orbitals, and have 7 valence electrons. A halogen is much more able to grab one single electron to fill its outter valence orbitals than it is to lose 7. Hydrogen, having only one valence electron, can go either way, but prefers to lose one. Couldn’t tell you why losing one is more energetically favoured than gaining one, though I guess it could be due to an extra electron resulting in additional repulsive forces (or maybe not, I’m no physicist). 

Is this homework? Could you share your attempts at this question and where you are stuck exactly?

Much of it comes from ~2015, when you made posts like this:

Also worth noting that you have been given good advice on this previously. 

2 hours ago, peterwlocke said:

thanks. why are you a curmudgeon?

We don’t delete posts. We do hide them. I’d rather not give RC the air time, personally. 

RenaissanceChemist has been banned as a result of being a likely sockpuppet and a definite pest. 

It was little more than a poorly veiled attempt to snipe at / about swansont, and clearly not posted for the purposes of genuine discussion. Such threads do not belong on this forum. 

It exists, but has been hidden. 

18 hours ago, Strange said:

And, of course, there is a bit of a history of senior researchers getting Nobel Prizes for work that their (often female) students or colleagues did (structure of DNA, discovery of pulsars).

Students doing the bulk of the bench work (which includes contributing ideas as well as performing experiments) is par for the course, though. Once you get to the point where you are in charge of your own group, you tend to be more of an administrator than an active bench scientist. The higher you go the truer it becomes. 

For chlorella, you can use OD (you should be able to find lit for wavelengths etc) or you could use a hemocytometer. I used to use the hemocytometer when I worked with chlorella, and it worked pretty well for what I needed, although it is time consuming. 

1 hour ago, Sensei said:

Yes, they are. Recently. Guy made thread, went to sleep, didn't manage to log in back, and the less than 24h later "thread closed". C'mon!

Wait at least a week to see if somebody is revisiting forum and logging at that time (and reluctant to reply for questions), prior closing his/her thread..

What thread are you talking about?