Many times, a problem will specify how much has decayed and you must use that information to determine how much remains. I would like to stress that the decimal amount is the amount that remains after a given number of half-lives. Just below are the amounts remaining after 2, 3, and 4 half-lives. However, please be aware that it is the decimal amount that will be used in the various calculations, not the percentage. At this point 0.5 of the original amount remains. This second example shows one half-life elapsed. Keep in mind that the decimal amount times 100 becomes the percentage. In other words, at the very start, before any decay has taken place, 100% of the material is on hand. The 1 represents the decimal fraction remaining. In this example, zero half-lives have elapsed. Let us use several different half-lives to illustrate this equation. (1/2) number of half-lives = decimal amount remaining

The order in which you use them depends on the data given and what is being asked. And that will be a good thing.ĭoing half-life problems is focused on using several equations. Later on, you may learn that approach to half-life calculations, one that uses calculus to develop the concept. What follows does not explicitly use the general chemical concept of kinetics. ChemTeam: Half-Life Radioactivity: Half-Life Ten Examples Probs 26-40 Probs 1-10 Problems involving carbon-14 Probs 11-25 Examples and Problems only (no solutions) Return to Radioactivity menu

Half life in 60 seconds