Posted by Krys on Tuesday, January 25, 2011 at 11:16pm.
I am confused about how to claculate half lives. Can you explain. ( How much of a 400 gm sample od gold is left after 10.8 days if the half life is 2.7)

Science Half Lives  DrBob222, Tuesday, January 25, 2011 at 11:21pm
This way.
k = 0.693/t_{1/2}
You don't have any units for the half life of 2.7 WHAT? Make sure unit for this agrees with unit below (in days).
Substitute k into the equation below.
ln(No/N) = kt
No = what you start with400 g
solve for N, the number left after time t.
k from above.
t = time = 10.8 days.

Science Half Lives  Krys, Wednesday, January 26, 2011 at 12:48am
2.7 days.. so the answer is 25 g ?

Science Half Lives  kiri, Wednesday, October 17, 2012 at 12:05pm
1. billion

Science Half Lives  Amber, Wednesday, September 24, 2014 at 12:58am
I don't know the answer to your question, but can some one help me with mine?
Question: After six halflives, what percentage of a radioactive sample will remain?
Please help me!, Thank you.
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