# exponential decay and half-life

Is there just one formula to calculate half life problems? What is the process or formula for solving these problems.

1. A 2.5 gram of an isotope of stontium-90 was formed in a 1960 explosion of an atomic bomb at Johnson island inthe Pacific test Site. The half -life of strontium-90 is 28 years. In what year will only .625 grams of this stontium-90 remain?

2. Actinium-226 has a hlaf-life of 29 hours. If 100 mg of actinium-226 disintegrates over a period of 58 hours, how many mg of actinium-226 will remain.

© BrainMass Inc. brainmass.com October 9, 2019, 7:12 pm ad1c9bdddfhttps://brainmass.com/chemistry/general-chemistry/exponential-decay-and-half-life-110908

#### Solution Summary

The solution is comprised of two exponential decay examples. It explains the half-life, decay constant, quantity remained relationship in detail.

$2.19