The electrodes in a fuel cell are called cathodes and anodes which one is negative and positive ?
99663
cathodes are positive
328575
reduction:  2e- + Cu2+ --> Cu      Eo = +0.34 V  cathode (+)\n\noxidation:   Zn   --> Zn2+ + 2e-   Eo = +0.76 V    anode (-)\n________________________________________\n\nZn  + Cu2+ --> Cu  +  Zn2+         Eo = +1.10V therefore cell spontaneous as written.
437234
More than likely DC.  By using direct current you are always keeping one end the anode and the other the cathode, one side always is "giving" and the other end always "recieving."  DC systems have a tendancy to corrode one end and slowly eat away at it.
1180598
The "power" in any electric current is 'voltage'.\n'Voltage' is the measure of the potential difference of electrons between two substances, and therefore the potential for electrons to be transferred between them.\nBatteries generate electricity through any one of several electrochemical reactions.  \nTwo different types of metals are placed in a catalyst (usually a liquid).  When a circuit is completed between the positive side and the negative side, electrolysis occurs - the above mentioned transferring of electrons through chemical reactions from one metal to the other.  The difference in potential felt between the  positive and negative charges (giving off an electron results in a positive charge, accepting it results in a negative charge) is again your volts.\nThe reaction continues until the battery reaches homeostasis (equilibrium, balance).\nIn some kinds of batteries applying an outside electric current properly can reverse the process - allowing you to recharge the battery.\nRechargeable batteries eventually become exhausted because of of oxidation of the polarizing metals or due to a 'memory' buildup.  'Memory' refers to a battery that is not completely discharged before it is recharged.  This is the major reason for the degradation of rechargeable battery life cycles.
528106
since reduction occurs at the cathode, it would be the Ag+, but it is relative to what your anode is.
495744
Well, if you run a current through saltwater (NaCl in water solution), two half-reactions are taking place in an electrolytic cell: \n2Cl- ---> Cl2 + 2e-  anode, oxidation (+)\n2H20 + 2e- ---> H2 + 2OH-  reduction, cathode (-)\nThe negative end is producing H2 gas, which bubbles out of solution, and hydroxide ions, which are basic.  So the stuff coming off of the negative end is basic, not acidic.
71215
Positive.  Current is typically shown flowing from a high (positive) electrical potential to a low potential, often ground.  Electrons would be attracted to the positive potential, and flow toward it, in the opposite direction that current is defined.
98419
I would use Carbon-Graphite electrodes for both the anode (+) and cathode (-) simply because they are cheap and effective.  The electrode you really need to be concerning yourself with is the anode since it is most prone to corrosion, you have much more freedom with the cathode.  I really dont see the need of using an expensive inert metal electrode, when graphite will do the job.
630577
A dry cell only has one comparment which uses a one solution where a voltaic cell has two seperate compartments for two different half reactions. They both have a catode and anode to conduct the electricty, but half cells are more expensive. The two have the same purpose though and that is to conduct electricty and also to produce a small current.
904938
positive or negative charge\n\nif it has an equal number of protons and electrons, it is neutral\n\nif it has an unequal number of protons and electrons, it has a charge and is an ion
884612
Because electrodes are either reducing agents or oxidizing agents, meaning, either of them are willing to give or recieve electrons. Cathodes are willing to donate electrons. Anodes are willing to take electrons. These are their chemical properties. If they do not have these properties, they wont be good electrodes. Now since ions are charged, they are less stable. To achieve stability, an ion, say a cation, will need to go to the cathode where the material is more than willing to give out extra electrons. Because of the electron donation, the cation will then be nuetral, thus more stable. Nature always favors the more stable.
631579
2 electrodes and a battery
721897
A fuel cell is an electrochemical energy conversion device. The core functioning unit of a fuel cell is a single 'cell' that combines fuel with oxidant in order to generate electricity, heat and waste. Usually, many such cells are combined into a "fuel cell stack". In turn, a fuel cell stack is combined with subsystems such as thermal management and fuel storage/delivery subsystems in order to produce a functional "fuel cell system".\n\nThere are five different types of fuel cell, based on the electrolyte used. In turn, there are further types of fuel cell that share an electrolyte - e.g. Polymer Electrolyte Membrane Fuel Cells (PEMFC) and Direct Methanol Fuel Cells (DMFC). \n\nEach type of fuel cell is suited to different applications, and the configuration of fuel cell system varies widely from application to application. Fuel cells have been produced in the sub 1 Watt range, right through to MegaWatt systems. Therefore, fuel cells have applications in just about every energy usage situation.\n\nThere are a number of significant advantages to using fuel cells in various applications, including diversity of fuels, efficiency, suitability for distributed generation and their quiet operation.\n\nYou will find more about 'What is a Fuel Cell' here: http://www.fuelcellmarkets.com/article_flat.fcm?subsite=1&articleid=696.\n\nDifferent markets (applications) for fuel cells are predicted to commercialise at different times. For example, stationary power plants, portable power packs and micro fuel cell systems for consumer electronics are all either commercial now, or are expected to commercialise this year. Transportation applications, perhaps the most visibly obvious to most people (i.e. fuel cell cars) are one of the furthest applications from commercialisation for a number of reasons.
770388
In electrochemistry, the Nernst equation gives the electrode potential (E), relative to the standard electrode potential, (E0), of the electrode couple or, equivalently, of the half cells of a battery. In physiology the Nernst equation is used for finding the electric potential of a cell membrane with respect to one type of ion.
427800
In each half-cell is a chemical undergoing either oxidation or reduction. In a full electrochemical cell, one side must be losing electrons (oxidation) in to its electrode while the other half-cell gains electrons (reduction). If the atoms/ions involved in the reaction are metal, the same metal is used for each electrode. If the atoms/ions involved in the reaction at each half-cell are not metal, obviously no electrode can be constructed out of it. Nonreactive metals such as platinum are used as a substitute. Finally, a salt bridge is necessary to provide electrical contact between the cells—but without the solutions mixing. This can simply be a strip of filter paper soaked in saturated potassium nitrate (V) solution.\n\nDifferent choices of substances for each half-cell results in varying potential differences. Each reaction is undergoing an equilibrium reaction between different oxidation states of the ions—when equilibrium is reached the cell cannot provide further voltage. In the half-cell which is undergoing oxidation, the closer the equilibrium lies to the ion/atom with the more positive oxidation state the more potential this reaction will provide. Similarly, in the reduction reaction, the further the equilibrium lies to the ion/atom with the more negative oxidation state the higher the potential.
357536
First you will need to work out what the two half equations are (Hint, have a look at a table of standard reduction potentials - these not only give Eo for each half - equation, but also the half - equation of course). URL below if you need it.\n\nSecond, record the values of each half equation, then use the formula:\n\n Eo cell = Eo cathode - Eo anode \n\nto get the cell voltage. (If you are not sure how to do this, try the link below or re post)\n\nThirdly, use the Nernst equation (should be either in your lecture notes or your text, if not try Googling "Nernst Equation") to calculate Eo under the conditions stated in part b of your question.\n\nI hope this helps.
1094903
Positive ions (Cation) are formed by a neutral atom losing electron(s), and Negative ions (Anion) are formed by atom gaining electron(s).  \n\nThe exact number of electrons an atom gains or loses are predictable.  Atoms gain or lose electrons so that they turn isoelectric with the closest neighboring Noble Gas.