To test the quality of water sources in her area, Shameka collects five samples from each water source and tests the quality of
1 answer:
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The answer is 1/16.
Half-life is the time required for the amount of a sample to half its value.
To calculate this, we will use the following formulas:
1.
,
where:
<span>n - a number of half-lives
</span>x - a remained fraction of a sample
2.
where:
<span>
- half-life
</span>t - <span>total time elapsed
</span><span>n - a number of half-lives
</span>
So, we know:
t = 10 min
<span> = 2.5 min
We need:
n = ?
x = ?
</span>
We could first use the second equation to calculate n:
<span>If:
,
</span>Then:
⇒
⇒
<span>
</span>
Now we can use the first equation to calculate the remained fraction of the sample.
<span>
</span>⇒
<span>⇒
</span>
Half-life is the time required for the amount of a sample to half its value.
To calculate this, we will use the following formulas:
1.
where:
<span>n - a number of half-lives
</span>x - a remained fraction of a sample
2.
where:
<span>
</span>t - <span>total time elapsed
</span><span>n - a number of half-lives
</span>
So, we know:
t = 10 min
<span>
We need:
n = ?
x = ?
</span>
We could first use the second equation to calculate n:
<span>If:
</span>Then:
⇒
⇒
</span>
Now we can use the first equation to calculate the remained fraction of the sample.
<span>
</span>⇒
<span>⇒
Answer : The correct option is, (C) 6
Explanation :
Oxidation-reduction reaction : It is a reaction in which oxidation and reduction reaction occur simultaneously.
Oxidation reaction : It is the reaction in which a substance looses its electrons. In this oxidation state increases.
Reduction reaction : It is the reaction in which a substance gains electrons. In this oxidation state decreases.
The given unbalanced chemical reaction is,
Half reactions of oxidation and reduction are :
Oxidation : ......(1)
Reduction : .......(2)
In order to balance the electrons, we multiply equation 1 by 2 and equation 2 by 3, we get:
Oxidation : ......(1)
Reduction : .......(2)
The overall balanced chemical reaction will be:
From this reaction we conclude that the electrons are getting transferred from iron to iodine and the number of electrons transferred are 6 electrons.
Hence, the correct option is, (C) 6