Technetium-99m is commonly used as a medical radioisotope in numerous medical diagnostic procedures yearly. The half-life of technetium-99m is 6.00 hours. After 1 day, a medical sample was found to contain 0.05 grams of technetium-99m. How many grams of technetium-99m were present initially?

Question

Quizplus · Accepted Answer

The half-life of technetium-99m is 6 hours. In 24 hours (1 day), there are 4 half-lives (24/6 = 4). After 4 half-lives, the amount of substance is reduced to (1/2)^4 = 1/16 of the original amount. If 0.05 grams remain, the initial amount was 0.05 * 16 = 0.8 grams.

Technetium-99m Is Commonly Used as a Medical Radioisotope in Numerous