What is the half-life of an isotope if 125 g of a 500 g sample of the isotope remains after 3.0 years?
1 answer:
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Answer:
Approximately .
Explanation:
Cathode is where reduction takes place and anode is where oxidation takes place. The potential of a electrochemical reaction () is equal to
.
There are two half-reactions in this question. and
. Either could be the cathode (while the other acts as the anode.) However, for the reaction to be spontaneous, the value of
should be positive.
In this case, is positive only if
is the reaction takes place at the cathode. The net reaction would be
.
Its cell potential would be equal to .
The maximum amount of electrical energy possible (under standard conditions) is equal to the free energy of this reaction:
,
where
is the number moles of electrons transferred for each mole of the reaction. In this case the value of
as in the half-reactions.
is Faraday's Constant (approximately
.)
.
The correct answer is
<span>c) very small and very large
Let's see this with a few examples:
1) if we have a very small number, such as
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<span>we see that we can write it easily by using the scientific notation:
</span>
<span>2) Similarly, if we have a very large number:
</span>
<span>we see that we can write it easily by using again the scientific notation:
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<span>
</span>
<span>c) very small and very large
Let's see this with a few examples:
1) if we have a very small number, such as
</span>
<span>we see that we can write it easily by using the scientific notation:
</span>
<span>2) Similarly, if we have a very large number:
</span>
<span>we see that we can write it easily by using again the scientific notation:
</span>
</span>