Answer: It will take 6 years for 7500 grams of X to reach 6900 grams.
Step-by-step explanation:
Expression for rate law for first order kinetics is given by:
where,
k = rate constant
t = age of sample
a = let initial amount of the reactant
a - x = amount left after decay process
a) for completion of half life:
Half life is the amount of time taken by a radioactive material to decay to half of its original value.
b) for 7500 g to reach to 6900 g
It will take 6 years for 7500 grams of X to reach 6900 grams.