Question

Using the chart, determine the amount of Co-57 present on January 21 if you had a sample of 8g on January 1st. A) 2 g B) 4 g C) 16 g D) 25 g

Answer 1

Answer:A

Explanation:because i got hundred on usatestprep

Answer 2

Answer:

A) 2 g

Explanation:

According to the graph, the half-life of Co-57 is 10 days. In twenty days (the amount of time between Jan 1 and Jan 21), two half-lives have passed, and, therefore, the amount of the sample has decreased by 50% twice. After the first ten days, 4g remain; after the second ten days, only 2g are left.