liambob1

So for tlc, in selecting the correct mobile phase and stationary phase what are the factors which influence what ones you choose, how do you decide what ones to use?

Thank you very much, it's greatly appreciated

As part of the experiment we used an acid to dehydrate the sucrose and see did this effect the rotary power , the result was inconclusive, what should have happened? And I know he wasnt 'twas silly of me

I checked back in my reports to the experiment and the solution we tested was a sucrose solution, I sought help not to get my errors thrown in my face John

We did the test of various substances, salacylic was one, we used methyl orange among others

In our instrumentation lab we have been using a polarimeter on salicylic acid tp measure the degree it rotates plane polarised light, I understand that it does this and the applications of this but Im confused about HOW it does this, I know it has something to do the vibration of molecules. If someone could help me clear this up I would appreciate It.

I was reading about a recent breakthrough by the fine folks at Trinity college here in Ireland, the article in question says that A hormone called Amylin, or Islet Amyloid Polypeptide (IAPP) has been discovered to a key underlying cause to type two diabetes and the main trigger for the disease because it gets deposited in the pancreas and causes the body to produce much greater levels of insulin than it normally would. It is claimed that a drug could be designed to suppress this hormone and thus bring insulin levels back down and prevent the onset of diabetes, My question is that would the suppression of this hormone have any serious adverse effects or cause any other complications. A brief discription of the article is available here

If any of the reactants or products are solids or liquids, their concentrations are equal to one because they are pure substances

Kc and kp are effected by: R = gas constant, (0.08206) T = temperature, nP = total moles of gaseous products nR = total moles of gaseous the mathematical relationship between the two constants, Kc and Kp, is: Kp = Kc(RT)^(nP - nR)

Clearly, but what I propose is not that the eel doesn't work. It is obvious that it does. I think there is a different explanation for it than just that the electric field surrounding the eel in a usual dipole shape is powerful enough to force a current through another fish. Furthermore, your wording seems to indicate that when people talk about "firing" the organ, they mean that before this, it was at electric equilibrium, and then it "fires" by the eel separating the charges in just a few seconds. That would require the eel to produce a gigantic amount of energy in a very short period of time. I was under the impression that it gradually built up the separation over time, if this is indeed the case and the electric field surrounding it can produce a force strong enough to drive a current through a remote target, then it would constantly be electrocuting everything around it, which I don't think is the case. So, if it is the case, as you suggest, that the eel electrocutes things just by becoming a dipole and the electric field around it is strong enough to force a current through other fish, then one of the following must be true: 1 - There is no "firing" of the organ (The fact that I have seen reference made to this "firing" or "discharge" in a number of places makes this seem unlikely) and the eel produces an extremely high potential difference within itself. or 2 - Usually, the eel is at electric equilibrium, it only separates charges when it is attacking. This would require the eel to produce a huge amount of energy very quickly, and it would be incorrect to call this a "discharge," because it is going from an uncharged state to a charged state.

That would indeed be a possibility. However, in order for it to occur in that manner, for the electric field to remotely force a current through a target fish, the voltage across the organ would need to be enormous. I have read that they are capable of creating potential differences of a few hundred volts, this is far too low, I believe.

I understand that, but that doesn't explain and nor as far say I can see does that page describe how the eel released the charge into the water and thus into its prey. it is not the details of the biological processes that I don't understand , but how that results in a current flowing in the target fish. My thinking is as follows: Firstly, I don't think it releases ions out into the water. Secondly, suppose it releases positive ions from one end of the organ. The negative charge that is still in the other end of the organ will be exerting a very large force on them and they will be pulled back to that part of the eel. The target fish has net charge of 0, so it wouldn't pull the charged particles towards it. All help is greatly appreciated

I find the ability of electric eels to use electricity offensively confusing. I can understand that it can achieve a separation of charge within an electric organ through biological processes in which I'm not very interested just now. According to some vague descriptions of how it works, it then "discharges" or "fires" the organ. I presume what this means is that it allows the organ to return to equilibrium, with a strong current briefly flowing through the organ itself. But how does this cause the target fish to be electrocuted? I would greatly appreciate it if anyone can offer an explanation of the physical processes occurring here, or direct me to somewhere where I might read more about it.

Hi there , I'm Liam, a student of Pharmaceutical Healthcare in the Dublin institute of technology in Ireland. And I'm a science-aholic