Sapling #12 (Week 9/10)

[Jessica Luong 3K]

A particular reactant decomposes with a half‑life of 167 s when its initial concentration is 0.318 M. The same reactant decomposes with a half‑life of 227 s when its initial concentration is 0.234 M.

I know that I will be using the second order half-life equation to find K, but for some reason, I keep getting the wrong answer. Which initial concentration and half-life value should I be using?

[Anthony_3C]

So I think the question asks you first to determine the order. It's gotta be 0 or 2nd because the half life changes with initial concentration. So you plug in and test and you know it's 2nd order. t1/2 for 2nd order is 1/k[A0], just plug in one of the 2 data and you'll get k: 167s = 1/k*[0.318]. k = 1/167*0.318

[Armen_Isayan_2L]

Hello! In order to solve this problem, you must utilize the second-order half-life equation, t1/2 = 1/k[A]0, except you must rearrange this equation so that k is isolated, k = 1/t1/2[A]0. By utilizing this rearranged equation you will be able to solve for the rate constant. If you are still having trouble, feel free to let me know so that I can further explain!