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:
I'm thinking observation vs inference
Explanation:
she does her research about the situation and then comes up with an idea. the idea can be seen as an inference since at the end of the article it says "proving to be more impossible than not", which leads me to believe it's more of an observation vs inference situation.
Answer:
Due to cell wall.
Explanation:
Scientists were able to easily identify the cells in plants first as compared to animal cell because the plant cell has cell wall while the animal cell has no cell wall only cell membrane. The structure of plant cell is just like the compartments and the cell wall provides the boundary between two cell which enable the scientist to see the plant cell first.
No estoy seguro que decir, pero sí es difícil
Answer: Inflammation
Explanation: Inflammation, is caused by the dilation of blood vessels which allows the passage of fluid, antibodies and WBC's into the infected body area
