Posted by c on Thursday, June 20, 2013 at 9:38pm.
60.0 grams of Th210 with a half life of 50,000 years is allowed to decay for 250,000 years. How much of the original quantity remains? In addition, Th210 decays via beta emission. Write the equation for its transmutation.

Chemistry H  DrBob222, Thursday, June 20, 2013 at 11:05pm
The long way.
k = 0.693/t_{1/2}
ln(No/N) = kt
No = 60
N = solve for N.
k from above.
t = 250,000
First number is atomic number. Second number is mass number.
90Th210 ==> 1e0 + 91Pa210