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:
Right now, I am in college for climatology, but before I decided on climatology, I was taking classes in Meteorology, the study of weather. So, I will answer your question. All meteorologists like to be right, but since the weather is so spontaneous, it is really hard to be right. Meteorologists use percentages because it helps them be professional. Also, because, different parts of the region where they are may or may not get the rain. I don't know where you are from, but I will use my hometown. In McAlester, Oklahoma, there may be a 70% chance of rain, but in another part of the region at Tulsa, Oklahoma ( which is 91 miles north of McAlester) there may be a 40% chance of rain. The difference in the percentages can vary from how stable the environment is, altitude, location, and terrain. That is two of the reasons why Meteorologists use percentages to predict weather.
Explanation:
The most important things for a cell<span> are oxygen in order to respire and Glucose, also for respiration. This is used in a process called glycolysis where the </span>cell<span> makes a chemical called ATP which is basically our energy
Hope this helped!</span>
The type of muscle that is responsible for maintain posture is VOLUNTARY. The correct option is B. Skeletal muscles are the ones who control posture and movement and they are voluntary in nature, that is, they are under the conscious control of man. The muscles that are responsible for maintain posture are: spinal, pelvic and abdominal muscles, hip muscles, lower leg muscles and shoulder and neck muscles.
For the generalized scheme of Alternation of generations (see p. 120), plants have two forms based on a genetic complement that are the Sporophytes (2N diploid) and Gametophyte (N haploid). The processes connecting the two stages are gametangia producing haploid spores and zygote cell growth producing haploid gametophyte. Group of answer choices
