+0  
 
0
1
870
1
avatar+97 

Carbon-14 (C14) decays by a nuclear process to form carbon-12 (C12). The rate of decay of C14 is directly proportional to the quantity of C14 present. The half-life of C14 (time taken for the mass of C14 to halve, eg 1.0kg to 0.5kg) is 5730 years. If you start with a 626 gram block of pure C14, what mass of C14 remains after 5300 years?

Mass of C14 at 5300 years (g) = [correct answer is 329.71]

 

Thanks Guys :)

 Sep 30, 2014

Best Answer 

 #1
avatar+33603 
+5

The radioactive decay equation is N = N0e-ln(2)t/τ where N is number of atoms (or mass in this case), N0 is initial number (or mass) t is time and τ is half-life  (ln is the natural logarithm, or log to the base e).  So:

Mass after 5300 years = 626*e-ln(2)*5300/5730 grams.  I'll leave you to crunch the numbers.

 Sep 30, 2014
 #1
avatar+33603 
+5
Best Answer

The radioactive decay equation is N = N0e-ln(2)t/τ where N is number of atoms (or mass in this case), N0 is initial number (or mass) t is time and τ is half-life  (ln is the natural logarithm, or log to the base e).  So:

Mass after 5300 years = 626*e-ln(2)*5300/5730 grams.  I'll leave you to crunch the numbers.

Alan Sep 30, 2014

6 Online Users

avatar
avatar