Cell Definition and 899 Threads

I've looked everywhere. Can someone tell me if there is a half cell potential for silicon? Si(0) ---> Si(4+) + 4e Every list of the galvanic series on the web that I have seen has no data for silicon.

For an electrochemical cell containing two metals how do I figure out which one reduces and which one oxidizes using standard reduction potentials? Thank you very much for the help.

Relevant equations int rest =emf - terminal potential / current or r=E-V/I The attempt at a solution Since Emf of a cell is inversely proportional to temp (From Nernst Equation of Emf of a cell), from the above equation, if temp is high, E is low, therefore r is low. So, acc. to me...

So my question is this does DMSO as someone in the lab I am working at says "it replaces the water in the cell" is that true?? From what I have read in journals a couple of journal articles they never said anything about it replacing the water. It did talk about thinning of the bilayer and...

I seriously need all the help I can get because I don't understand these last two questions of this essay, I got everything else figured out and done except for the two at the bottom. Details; "A scientist designed the following experiment to test the limits of cell population growth. Cells...

Homework Statement In its resting state, the membrane surrounding a neuron is permeable to potassium ions but not permeable to sodium ions. Thus, positive K ions can flow through the membrane in an attempt to equalize K concentration, but Na ions cannot. This leads to an excess of Na ions...

Enuma's thread got me thinking why these isn't more buzz for the hydrogen cars like the Honda FCX, GM Sequel, Nissan Frontier, BMW 7...

Homework Statement he fluid within a living cell is rich in potassium chloride, while the fluid outside it predominantly contains sodium chloride. The membrane of a resting cell is far more permeable to ions of potassium than sodium, and so there is a transport out of positive ions, leaving...

Homework Statement The membrane surrounding a living cell consists of an inner and an outer wall that are separated by a small space. Assume that the membrane acts like a parallel plate capacitor in which the effective charge density on the inner and outer walls has a magnitude of 5.77 x 10-6...

[SOLVED] primitive cell Homework Statement http://en.wikipedia.org/wiki/Primitive_cell Could someone give me a mathematically rigorous of a primitive cell? I have read like 4 different definitions and none of them seem mathematically rigorous. I think Wikipedia's definition is particularly...

Hi all, sorry if this has been asked before but i can't find a thread with the info I'm after. I'm doing an access course at lvl3 (AS/A2) which includes biology and I'm stuck on the following question as part of an assignment I'm to hand in next week. Q: Suggest an explanation for the fact...

Homework Statement Hi all, In school, I tried to investigate how the emf (voltage) of a fruit cell varies with temperature. I took ~200ml of freshly squeezed orange juice, 2 copper electrodes, a voltmeter, heater and thermometer. I set up everything, and got an initial voltage of somewhere...

http://www.sciam.com/article.cfm?id=news-bytes-of-the-weekis

Hey everyone, I was reading a Biology text and it mentioned the Cell Theory, and at the same moment I thought of this question. Why do we still consider it a theory, if we have seen it occur many times by observing microscopes of differing abilities. Shouldn't we consider it a fact now that...

I hope someone can help me with my coursework by making sure my method is ok and is actually correct for my experiment. Note. I will not actually be doing this it is just a plan of what I could do! 1. I am provided with a cell of approcimate EMF 1.5V, an approximate internal resistance of 1Ω...

does anyone know how to calculate the Transformation efficiency?

What is the maximum useful work which can be obtained from a hydrogen-oxygen fuel cell that produces 1.96 kg of water at 25°C? How do we approach this problem? I guess -Ecell x charge = w?

The spectrum for cell phones is typically in the 850 MHz range. E=hv yields around 3.515E-6 eV. The lowest natural state electron binding energy is on the order of 10 eV >> 3.515E-6. Is this enough to dispel the "correlation"? Are there any other particle interaction mechanisms that would...

IO3-(aq) ---> I2(s) balanced the 2nd one to 12 H + 2IO3 + 5e- ---> I2 + 6H2O can anyone tell me the Ecell value for this equation?

How long could you make/lengthen the telomere of a cell?

First of all, why do cell die? Should it live forever? I am guessing that by the time cell indicates it needs food, it is already hungry, and the time it takes food to get to the cell...it suffers damage...and it is this small damage that keeps the cell aging till it dies. I read...

[SOLVED] Combined resistance of a cell and an ammeter Homework Statement I had to do a lab where a 105cm 28 swg wire was used to find the combined resistance of a cell and an ammeter. The only apparatus was a switch, 1.5v cell, 0-1A ammeter, 105cm & 20cm wires and connecting wires. Switch...

Homework Statement I would like to have some of my homework problems checked. I looked in the book, and answered these the best I could. My answers are in bold. Thanks in advance for the help! Homework Equations N/A. The Attempt at a Solution 1. Which functional plant cells lack a...

Homework Statement I'm trying to calulate the efficency of a small hydrogen fuell cell that I built. I have all of the measurements, but I'm not coming up with a resonable effiency. Homework Equations \frac{P OUT}{P IN}x 100 The power to electrolyze the water is the P IN. 3.25 W...

Plasmolysis, diffusion, osmosis, imbibition My Reason: its the shrinkage of cell. The rest are process involved in the transport of water

Homework Statement http://img143.imageshack.us/img143/7135/electrolysisrf2.jpg What is the ratio of number of moles of copper deposited to the number of moles of mercury deposited? {n(Cu):n(Hg)} 2. The attempt at a solution Well the species present are; \begin{array}{l} Cu^{2 + } /SO_4...

I basically want to identify the fill-factor of a photo voltaic cell by calculating the ratio of maximum power (Vmp x Jmp) divided by the short-circuit current (Isc) and open-circuit voltage (Voc) in light current density. 1. How am i suppose to set up the circuit, should a voltmeter be...

The Peltier effect is the reverse of the Seebeck effect; a creation of a heat difference (between two joint) from an electric voltage. This temperature difference gives rise to a seebeck voltage which is opposite to the voltage of the cell. So we can resonably conclude that it can contribute...

Dear peeps, i am currently facing a problem here. i am tasked to place PV cells within an area and maximize the efficiency of PV cell by focusing sunlight on the cell itself. I am wondering if it is possible. I am thinking of placing 3 cells in a U shape. 1 at the bottom facing up and 2 at the...

http://www.nextenergynews.com/news1/next-energy-news-betavoltaic-10.1.html I cam across this article. It is horribly written from a scientific standpoint and lacks some necessary information on how the device works. But the basics are... Tritium is the beta source, porous silicon matrix...

Most batteries have only two terminals with symbols ''+'' and ''-''. I uderstand the function of two terminals. But almost all the cell phone batteries I have seen have more than two terminals. What is the reason for having more than two terminals? Please check this link...

Hi all, i am relative new here and i have an enquiry which i really wish to see if anyone can help me out with this. From my understanding, photovoltaic cell works by using photons from light to generate eletricity. From what i know is that the lower the wavelength of light, the higher is the...

I have a question regarding a load cell application I am working on. I am designing a loss in weight feeder system and would like to use a single load cell for my hopper weight. Upon preliminary trials, I mounted the load cell on one side of the hopper and hinged the other. This does not give me...

Homework Statement If an open cell is defined as (a1,b1) X (a2,b2) X ... (an,bn) in R^n and closed cell is defined as [a1,b1] X [a2,b2] X ... [an,bn], then every open set in R^n contains an open-n-cell and a closed-n-cell. Homework Equations Def: An open set is a set which has all...

I can't find the answer on the net..if anyone taken cell bio. Can you guys help me out :) 1. how does the structure of fucus differ from the green algae? 2. how is a holdfast different from a plant root? 3. consifering where fucus lives, what do you think is the function of its air...

Hello! I'm very interested in solar cell tehnology. I know that the main material used is crystalline silicon. Is it possible to buy all the materials that are necessary and to make the solar cell at home conditions? I hope that this process is not very complicated and laboratory isn't needed...

I heard an interview with Darwin Prockop from Tulane's Center for Gene Therapy. It was very interesting, especially the discussion about cells which function to repair damaged cells. The interview may be available next week. Meanwhile - Fascinating stuff! Faculty -...

Can anyone tell me if it is right to say that maximum power of a hydrogen oxygen fuel cell varies directly (with constant efficiency) with gas flow rate at constant pressure at room temperature

Sex cell? Quick question: Does every sperm cell in a male testicle contain the same genes, or can some sperm cells contain different genes, even though they are from the same person?

Homework Statement Calculate the maximum packing fraction of the unit cell volume that can be filled by hard spheres in the Hexagonal structure Relevant eq: Volume of spheres is number of lattice points multiplied with the maximum volume of one sphere. The Attempt at a Solution I...

Has anybody heard of this myth/urban lengend? Any thoughts on how feasible it is? This only applies to cars that can be unlocked by that remote button on your key ring. Should you lock your keys in the car and the spare keys are home, and you don't have "OnStar," here's your answer to the...

Even when we put our home phone numbers on the no call list, charitable organizations are still allowed to call. It looks like we are about to go through the same thing with our cell phones. http://www.abcnews.go.com/WN/story?id=3479517&page=1

I keep seeing all of these cell phone ads that only talk about playing music, as if that is the only reason to buy one. I thought you were supposed to talk on them. What do you buy a cell phone for?

Hi i recently acquired an ammeter with a shunt can anyone explain how to wire this so i can measure amps in an electrolytic cell. Does the positive lead have to be wired across the shunt so that it doesn't burn out the lcd display. I've never used such an ammeter so any suggestions will be...

Hello, I am working on a project where I will have to do some shear cell testing, I have some basic under standing (very basic). and I have done some research on the internet. I have a shear cell tester. it is very basic, geared motor with a rod to push on sample , which is under a weight. I...

Calculate the potential (voltage) of a standard cell with these half-cell reactions: Ni(s) -----> Ni2+ + 2 e- 2 e- + Cl2(g) -----> 2 Cl- :cry:

This is a bit unrelated, but I think this should go in this section here. You are all pretty savvy on this forum, so I'm wondering if you all know of any cell phones which allow you to record entire conversations?

ok... here is something interesting. I take it most of you haven't heard, but the most populated state in australia (New South Wales) has just passed a bill (act of parliament) through the lower house to legalise stem cell research in the state. Do you agree or disagree with this...

Hey, I recently read that they made a 40% efficient solar cell... what does this actually mean? How do they calculate this efficiency... and how much power do these cells actually produce? and what's with the mono and poly crystalline titles that they get? what does that mean?? Any info...

I need help thinking of ideas for slides. I have "How it works", "benefits", "challenges", "Physics behind it", "Hydrogen vehicles", "Why Hydrogen", "What is a fuel cell", "Uses", "efficiency", "Fuel cell configurations". I can't think of anything else.