For each of the following, indicate if the number of half-lives elapsed is: 1. one half-life 2. two half-lives 3. three half-lives a. a sample of ce-141 with a half-life of 32.5 days after 32.5 days b. a sample of f-18 with a half-life of 110 min after 330 min c. a sample of au-198 with a half-life of 2.7 days after 5.4 days

Explanation:

The number of half-lives elapsed, n, is calculated dividing the time by the half-life time:

a. A sample of Ce-141 with a half-life of 32.5 days after 32.5 days

b. A sample of F-18 with a half-life of 110 min after 330 min

c. A sample of Au-198 with a half-life of 2.7 days after 5.4 days

2h2o2--> 2h2o + o2

this reaction is of the spontaneous decomposition of hydrogen peroxide down into water and oxygen.

add 2 molecules of hydrogen peroxide and 2 molecules of water. since oxygen is naturally diatomic, the total number of atoms of each element is now the same on both sides of the equation so it is balanced.

this may not be entirely correct but let me know.