The radioactive decay obeys first order kinetics
the rate law expression for radioactive decay is
![ln\frac{[A_{0}]}{[A_{t}]}=kt](https://tex.z-dn.net/?f=ln%5Cfrac%7B%5BA_%7B0%7D%5D%7D%7B%5BA_%7Bt%7D%5D%7D%3Dkt)
Where
A0 = initial concentration
At = concentration after time "t"
t = time
k = rate constant
For first order reaction the relation between rate constant and half life is:

Let us calculate k
k = 0.693 / 72 = 0.009625 years⁻¹
Given
At = 0.25 A0

time = 144 years
So after 144 years the sample contains 25% parent isotope and 75% daughter isotopes**
Simply two half lives
Neutralization is the process in which anacid and base react to give salt and water
Answer:
1.5 hours or 90 minutes
Explanation:
Velocity = d/t
V = 64 mi / hour or 96 mi / 9 min OR 16 mi / 15 min
D = 96 miles
Velocity * Time = Distance
Time = Distance / Velocity
T = 96 mi / 64 mi / hour
96 / 64 = 1.5 mi per hour
T = 1.5 hours or 90 minutes
Answer:
Molarity is the number of moles in a liter of a substance.
Molarity= Mole/volume
Mass= 10g
Molar mass of Carbon=12g
To calculate the mole we use the formula: mole= mass/molar mass
Mole = 10g/12g
Mole = 0.83
Molarity= 0.83/500 =0.0017moles per liter