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.
The type of muscle found at the heart is the cardiac muscle tissue. This tissue has the phyical striped characteristic of a skeletal muscle tissue and works like a involuntary muscle because it works without our control
This type of tissue is packed wirh mitochondria which provides it with alot of energy. This is very crucial becaise the heart has to constantly beat
I think it would be D. because your hypothesis wasn't correct.
The law of conservation of mass states that atoms cannot be created not destroyed, so they could not have destroyed it. This means that the experiment had to be open (which means there is no barrier that keeps all the solution in, like a plug or a bag). When the liquid in the equation turned into gas, the gas floated away from the solution, making the ending mass smaller than the beginning.
Because it's where they live.
