Hi, can you post what you need help with??
The Half life is the time taken for a radioisotope or a radioactive substance to decay by half its original amount. The half life of carbon 14 is 5600 years.
Original mass is 100%
Remaining amount is 24%
Therefore; 0.24 = 1 × (1/2)^n
n = log 0.24/log 0.5
= 2.06
therefore, the age of the fossil is 5600×2.06
= 11529.8
≈ 11529 years
Answer: Molarity of the solution: 0.12
Molarity of sulfate ion: 0.360
Molarity of aluminum ion: 0.240
Explanation:
I’m not sure if that’s what you’re looking for
Answer : The concentration of A after 80 min is, 0.100 M
Explanation :
Half-life = 20 min
First we have to calculate the rate constant, we use the formula :



Expression for rate law for first order kinetics is given by:

where,
k = rate constant = 
t = time passed by the sample = 80 min
a = initial amount of the reactant = 1.6 M
a - x = amount left after decay process = ?
Now put all the given values in above equation, we get


Therefore, the concentration of A after 80 min is, 0.100 M