Answer:
16.7 days
Explanation:
We are given;
A radioactive isotope Iodine-131`
The decay rate is 0.138 d⁻¹
The percent decayed is 90%
We are suppose to calculate the number of days for the decay.
![In(\frac{[A_{0}]}{[A]})=kt](https://tex.z-dn.net/?f=In%28%5Cfrac%7B%5BA_%7B0%7D%5D%7D%7B%5BA%5D%7D%29%3Dkt)
Where, ![[A_{0}]](https://tex.z-dn.net/?f=%5BA_%7B0%7D%5D)
is the initial concentration and ![[A]](https://tex.z-dn.net/?f=%5BA%5D)
is the new concentration.
![t=In(\frac{[A_{0}]}{[A]})/k](https://tex.z-dn.net/?f=t%3DIn%28%5Cfrac%7B%5BA_%7B0%7D%5D%7D%7B%5BA%5D%7D%29%2Fk)
Assuming the initial concentration is x, then the final concentration after 90% decay will be 0.10x
Therefore;
![t=In(\frac{[x]}{[0.10x]})(\frac{1}{0.138})](https://tex.z-dn.net/?f=t%3DIn%28%5Cfrac%7B%5Bx%5D%7D%7B%5B0.10x%5D%7D%29%28%5Cfrac%7B1%7D%7B0.138%7D%29)
![t=In(\frac{[1]}{[0.10]})(\frac{1}{0.138})](https://tex.z-dn.net/?f=t%3DIn%28%5Cfrac%7B%5B1%5D%7D%7B%5B0.10%5D%7D%29%28%5Cfrac%7B1%7D%7B0.138%7D%29)
Time = 16.7 days
Therefore, it will take 16.7 days for 90% of I-131 to decay to Xe-131
In every balanced chemical equation, each side of the equation has the same number of <u>atoms</u> of reactants and products.
For example, let's take this chemical equation.
This is the chemical equation for carbon monoxide reacting with dihydrogen to form octane and water.
8 CO + 17 H2 → C8H18 + 8 H2O
On this side, we have 8 carbon monoxide atoms and 34 dihydrogen atoms.
On the other side, we have 8 carbon atoms and 18 hydrogen atoms + 16 hydrogen atoms.
Therefore, even though the coefficients are different there is still an equal number of atoms on each side.
8 Carbon Monoxide , 34 Dihydrogen = 8 Carbon Monoxide + 34 Dihydrogen
Answer:
true
Explanation:
A single replacement reaction is a reaction that an element is displaced with another element in a compound
A+BC------AC+B
Mg+2HCl-------MgCl2+H2
