The mass of substance left after 7 days is 13.09 g
The mass of substance left, N is given by
N = N₀exp(-λt) where λ = decay constant and N₀ = initial mass of substance present = 24 g and t = time
Also, λ = 0.693/t' where t' = half-life of iodine = 8 days
So, λ = 0.693/t'
λ = 0.693/8
λ = 0.086625/day
Since the mass of substance left is N = N₀exp(-λt) and we require the mass of substance after t = 7 days,
N = N₀exp(-λt)
N = 24 gexp(-0.086625/day × 7 days)
N = 24 gexp(-0.606375)
N = 24 g × 0.5453
N = 13.09 g
So, the mass of substance left after 7 days is 13.09 g
Learn more about radioactive decay here:
brainly.com/question/23705307
Answer:
8+10+8+10=36+ 2 x 3.14 x radium/2
Step-by-step explanation:
In the given question, there are several information's of immense importance. using these information's the correct and the required answer can be determined. It is given that an unknown number has to be found from the information's provided.
Let us assume the unknown number = x
Then
3x + 3 = 2x -1
3x - 2x = -1 -3
x = -4
So the unknown number is -4.
It should be remembered that these are trick questions and it is important to go through each lines very carefully to understand the inner meaning.