# Chemistry

How much time in years (assume a 365 day yr) would it take for a 1.6678g sample of 239Np to decay to a mass of 0.8671g if it has a half life of 2.030*10^5s

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1. k = 0.693/t1/2
Substitute k into the equation below.

ln(No/N) = kt
No = 1.6878
N = 0.8671
k fro above.
Solve for t (in seconds) and change to years.

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posted by DrBob222
2. Thank you so much DrBob222

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posted by Jude

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