Lanthanum-138 has a half-life of 105 billion years. after 525 billion years, how much of a 240 g sample of this radioisotope will remain?

nevermind, i got 7.5g and was right

7.50 grams of radioactive isotope will remain

Explanation:- Radioactive decay follows first order kinetics

Half-life of sample of lanthanum-138 = 105 billion years

N = amount left after time t  = ?

= initial amount = 240 g

= rate constant  =

t= time  = 525 billion years

Putting in the values, we get

it had to transfer to a care and maintenance mode

answer:

the reaction is type of combination reaction.

explanation:

on the product side, there are 2 molecules of bonded to fe   which means one atom of fe are combined two molecules of . so, balanced chemical equation becomes :

this reaction follows the reaction type of combination reaction. a combination reaction is defined as chemical reaction in which reactants combines together to form a single product.