Carbon-14 emits beta radiation and decays with a half-life (t) of 5730 years. Assume that you start with a mass of 6000 g of carbon 14. How many grams of the isotope remains at the end of four half-lives?

375g of a carbon-14 isotope

Explanation:

From

N/No = (1/2) t/t1/2

N = mass of isotope remaining after time (t)

No = mass of isotope present at the beginning

t = time taken for mass of isotope to decrease to N

t1/2 = half life of the isotope.

Since 1 half-life = 5730 years = t1/2

Four half lives = 4 (5730) years = t

No = 6000g of isotope

Then we substitute into the formula

N/6000 = (1/2) ^4 (5730) / 5730

N/6000 = (1/2) ^4

N = (1/2) ^4 * 6000

N = 375g of a carbon-14 isotope