Question

The isotope sodium-22 has a half life of 2.60 years. What is the 1st order rate constant in inverse years?

I am using the Ln (A/A0) = -Kt formula. Is that correct?

Answer 1

Yes, that is right if yu use it correctly. To use it, just substitute 100 for Ao and 50 for A and solve for t which then will be t_1/2 Actually it doesn't matter what number you pick for Ao as long as A is 1/2 that. Another way and slightly shorter is to tkae ln 1/2 (which is 0.693), then
k = 0.693/t<sub>1/2<sub>

Answer 2

Thank you!!!