The half-life of the carbon isotope C-14 is approximately 5,715 years. If the amount left after 4,000 years is 1.3 g, what is the amount after 8,000 years? Round your answer to three decimal places.
A) 0.800 g
B) 0.628 g
C) 1.300 g
D) 0.303 g
E) 1.601 g

Question

The half-life of the carbon isotope C-14 is approximately 5,715 years. If the amount left after 4,000 years is 1.3 g, what is the amount after 8,000 years? Round your answer to three decimal places. ​
A) 0.800 g
B) 0.628 g
C) 1.300 g
D) 0.303 g
E) 1.601 g

Quizplus · Accepted Answer

The amount of C-14 left after 8,000 years is 0.800 g. This is because the half-life of C-14 is 5,715 years, which means that after 5,715 years, half of the original amount of C-14 will be left. After another 5,715 years, half of the remaining amount will be left, and so on. So, after 8,000 years, the amount of C-14 left will be 1.3 g * (1/2) ^ (8000 / 5715) = 0.800 g.

The Half-Life of the Carbon Isotope C-14 Is Approximately 5,715