What you need to do is find 1/8 of 50
you can just divide 50 by 8 to get 6.25
so now you have to find how many days it will take till there are 6.25 grams of iodine left
every 8.1 days its mass is split in half
so start splitting it in half and every time you do, you add 8.1 days
50/2 =25 8.1
25/2 =12.5 + 8.1
12.5/2= 6.25 +8.1
now you have reached 1/8 of the original amount of Iodine-131
so to find how long it took just add 8.1+8.1+8.1
(this is the same as 8.1x3)
which equals 24.3
it will take 24.3 days for Iodine 131 to decay to 1/8 of its original mass.
(good luck on the regent if thats what your studying for :)
The answer is 4), see the picture
The rate law for the reaction : r=k.[A]²
<h3>Further explanation</h3>
Given
Reaction
A ⟶ B + C
Required
The rate law
Solution
The rate law is a chemical equation that shows the relationship between reaction rate and the concentration / pressure of the reactants
For the second-order reaction it can be:
1. the square of the concentration of one reactant.
![\tt r=k[A]^2](https://tex.z-dn.net/?f=%5Ctt%20r%3Dk%5BA%5D%5E2)
2. the product of the concentrations of two reactants.
![\tt r=k[A][B]](https://tex.z-dn.net/?f=%5Ctt%20r%3Dk%5BA%5D%5BB%5D)
And the reaction should be(for second order) :
2A ⟶ B + C
Thus, for reaction above (reactant consumption rate) :
![\tt r=-\dfrac{\Delta A}{2\Delta t}=k[A]^2](https://tex.z-dn.net/?f=%5Ctt%20r%3D-%5Cdfrac%7B%5CDelta%20A%7D%7B2%5CDelta%20t%7D%3Dk%5BA%5D%5E2)
Answer:
nitrogen, oxygen, argon, carbon dioxide, neon, helium, krypton, hydrogen, and xenon. It does not include water vapor because the amount of vapor changes based on humidity and temperature.