Fuel cells can make an electricity from a simple electrochemical
reaction in which oxygen and hydrogen combine to form water. There are several
different types of fuel cell but they are all based around a central design
which consists of two electrodes, a negative anode and a positive cathode.
These are separated by a solid or liquid electrolyte that carries electrically
charged particles between the two electrodes. A catalyst, such as platinum, is
often used to speed up the reactions at the electrodes. Fuel cells are
classified according to the nature of the electrolyte. Every type needs
particular materials and fuels and is suitable for any applications. The
article below uses the proton exchange membrane fuel cell to illustrate the
science and technology behind the fuel cell concept but the characteristics and
applications of the other main designs are also discussed. Proton Exchange Membrane Fuel Cells (PEMFC)
The hydrogen ions permeate across the electrolyte to the
cathode, while the electrons flow through an external circuit and provide
power. Oxygen, in the form of air, is supplied to the cathode and this combines
with the electrons and the hydrogen ions to produce water. These reactions at
the electrodes are as follows:
Anode: 2H24H+ + 4e-
Cathode: O2 + 4H+ + 4e- 2H2O
Overall: 2H2 + O22H2O + energy
PEM cells operate at a temperature of around 80°C. At this
low temperature the electrochemical reactions would normally occur very slowly
so they are catalysed by a thin layer of platinum on each electrode.
Answer:
Trees and birds have a commensalism relationship. The birds benefit from having a place to build their nests, while the trees are unharmed and not impacted by the bird’s presence.
Explanation:
Answer:
38.
Explanation:
All water that are present in soil is not available for the plants. Gravitation water is present in soil due to the gravitational force. The gravitation water remains for short time and cannot be consumed by the plants.
The capillary water is available to the plants and this water is attained in the soil pores. The total water present in soil sample is 100 ml. 62ml is gravitation water. The volume of capillary water = total water - gravitation water = 100 - 62 = 38ml.
Thus, the answer is 38ml.
Answer: A. In the electron transport chain, a series of reactions move electrons through carriers.
B. The products of the electron transport chain are H2O and either NAD or FAD.
E. The electron transport chain is a series of oxidation-reduction reactions that occur in the inner mitochondrial membrane.
Explanation:
the best suitable statement is it transfers energy stepwise from one compound to another, The electron transport chain is a series of proteins and organic molecules found in the inner membrane of the mitochondria. Electrons are transferred from one member of the transport chain to another in a series of redox reactions.
