Posted by Laura on .
The halflife of tritium is approximately 12 years. What will be the molar ratio of tritium to helium3 in a sealed sampel after 25 years?

CHemistry 
DrBob222,
k = 0.693/t_{1/2}
Solve for k and substitute in the equation below.
ln(No/N) = kt
Solve for No/N
Then you want [N/(NoN)]. Check my thinking.