There is a 50 g sample of ra-229. it has a half-life of 4 minutes. how much will be left after 12 minutes? a. 3.13 g b. 6.25 g c. 12.5 g d. 25 g

It's B. 6.25

first divide 50/2

then divide 25/2

after that divide 12.5/2

Then you get 6.25

Hope it helps!

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.