<u>Answer:</u> The amount of Iodine-131 remain after 39 days is 0.278 grams
<u>Explanation:</u>
The equation used to calculate rate constant from given half life for first order kinetics:

where,
= half life of the reaction = 8.04 days
Putting values in above equation, we get:

Rate law expression for first order kinetics is given by the equation:
![k=\frac{2.303}{t}\log\frac{[A_o]}{[A]}](https://tex.z-dn.net/?f=k%3D%5Cfrac%7B2.303%7D%7Bt%7D%5Clog%5Cfrac%7B%5BA_o%5D%7D%7B%5BA%5D%7D)
where,
k = rate constant = 
t = time taken for decay process = 39 days
= initial amount of the sample = 8.0 grams
[A] = amount left after decay process = ?
Putting values in above equation, we get:
![0.0862=\frac{2.303}{39}\log\frac{8.0}{[A]}](https://tex.z-dn.net/?f=0.0862%3D%5Cfrac%7B2.303%7D%7B39%7D%5Clog%5Cfrac%7B8.0%7D%7B%5BA%5D%7D)
![[A]=0.278g](https://tex.z-dn.net/?f=%5BA%5D%3D0.278g)
Hence, the amount of Iodine-131 remain after 39 days is 0.278 grams
Answer:number 2
Explanation:
the definition of photosynthesis is that carbon dioxide and water changes into sugar and oxygen