Answer and Explanation:
The half-life of a substance is the time it takes for half of the substance to decay. After one half-life, half of the original substance remains, and after two half-lives, one-quarter of the original substance remains. Therefore, after n half-lives, the fraction of the original substance that remains is (1/2)^n.
In this case, after 25 half-lives, the fraction of the original 800 grams of Chromium-48 that would remain is (1/2)^25, or approximately 0.0000000298. Multiplying this fraction by the original amount of 800 grams gives us the amount that would remain: 0.0000000298 * 800 = 0.0000238 grams.
So, after 25 half-lives, approximately 0.0000238 grams of the original 800 grams of Chromium-48 would remain.