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January 25, 2015

January 25, 2015

Posted by **Colby** on Tuesday, August 27, 2013 at 9:41pm.

I am confused on what number to start with

- Chem -
**DrBob222**, Tuesday, August 27, 2013 at 11:49pmYou have the half life, Use that to calculate k.

k = 0.693/t_{1/2}

Then

ln(No/N) = kt

Use 100 for No

Use 12.5 for N

Substitute k from above.

Solve for t in hours if you use t_{1/2}in hours.

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