The half-life for a 100-gram sample of radioactive element X is 5 days. How much of element X remains after 10 days have passed?
a
12.5 g
b
10o g - no change
c
50 g
d
25 g
The half-life of element X is 5 days, which means that after 5 days, half of the sample will remain. After 10 days, two half-lives have passed, so we need to divide the initial sample of 100 grams by 2 twice.
100 g / 2 = 50 g (after 5 days)
50 g / 2 = 25 g (after 10 days)
Therefore, the answer is d) 25 g.