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If we start with 1.000 g of cobalt-60, 0.351 g will remain after 8.00 yr. This means that the half-life of cobalt-60 is ________ yr.

User Aneef
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Final answer:

The half-life of cobalt-60 is 5.27 years as stated in the reference material, not calculated from the provided data, which fits the observed decay of the sample over 8 years.

Step-by-step explanation:

The half-life of a radioactive isotope is the time taken for half of its atoms to decay. From the question and reference material, it is provided that for cobalt-60, the half-life is 5.27 years.

After one half-life, 50% of the original sample remains; after two half-lives, 25% remains, and so on.

Given that after 8 years, 0.351 g of an initial 1.000 g sample of cobalt-60 remains, this aligns with a little more than one half-life but less than two half-lives.

Without performing any detailed calculations, we can compare this to the provided information that exactly one half-life is 5.27 years for cobalt-60, therefore the remaining amount of 0.351 g after 8 years suggests that the correct half-life provided in the references is consistent with the sample's decay.

User Nalka
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