To solve this problem, we need to determine how many half-lives have passed.
Since the half-life of sodium-24 is approximately 15 hours, we can divide the total time passed by 15 to find the number of half-lives.
Let's call the total time passed "t" hours. Since only one-eighth of the sodium-24 remains, this means that seven-eighths (or 7/8) of the sodium-24 has decayed.
So, after one half-life, only half of the original amount remains. This can be represented as 1/2.
After two half-lives, only one-fourth (1/2 * 1/2 = 1/4) of the original amount remains.
After three half-lives, only one-eighth (1/2 * 1/2 * 1/2 = 1/8) of the original amount remains.
This means that three half-lives have passed.
Therefore, the total time passed, "t" hours, is equal to 3 half-lives * 15 hours per half-life.
t = 3 * 15 = 45 hours.
Therefore, the answer is a) 45 hours.
Sodium-24 has a half-life of approximately 15 hours. If only one-eighth of the sodium-24 remains, about how much time has passed?
a
45 hours
b
30 hours
c
15 hours
d
60 hours
1 answer
1 answer