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>
Humans get<span> the </span>nitrogen<span> they need by eating vegetebles or other meat that contain </span>nitrogen<span>. hope it helps :)</span>
Answer:
IHD = 0; no unsaturation in the formula
Explanation:
The IHD is also known as the degree of unsaturation formula. This formula is commonly used to get an idea of how many unsaturations a molecule has, and in this way, we can get an approach of the type of compound we are treating. For example, if this number is 1, it means that the compound has at least one unsaturation and it could be a double bond or just cyclical compound.
The IHD is calculated using the following expression:
IHD = (a + 1) - (b + x - c)/2 (1)
Where:
a: number of carbon
b: number of hydrogens
c: humber of nitrogens
x: number of halogens.
Now, we have the formula C₄H₉Cl, let's identify a, b, c and x:
a: 4 carbons; b = 9 hydrogens; C = none; X: 1 chlorine
Replacing in (1) we have:
IHD = (4+1) - (9+1)/2
IHD = 5 - (10/2)
<h2>
IHD = 0</h2>
So this number is 0, which means that the molecule does not have any kind of unsaturation (Non double bond, multi bond or cyclical).
Hope this helps