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I think it depends on the units in the rest of the problem. If it is stated that the rate is mol/L- min, then the k will probably by 1/min. However, if nothing is given in terms on units in the rest of the problem, I think it would be best to use time units as seconds.
I think it would be a good idea to convert time to seconds if the problem doesn't ask otherwise. If needed, after finding k (with seconds as your units of time), you can always use conversion factors to change the seconds into another unit of time.
Adam Enomoto 1L wrote:Reaction A: k = 2.3 M-1s-1
Reaction B: k = 1.8 Ms-1
Reaction C: k = 0.75 s-1
How do we know which one is a zero order reaction just given the units?
I would just try to memorize the units for at least the first few orders.
I don't think the math of the problem is messed up, simply on a logistics level, when a different unit is used. its all about keeping track of your units. Also it will be easier to keep the units the same as the units of the answer you are trying to find
It's dangerous to make blanket statements of ALL PROBLEMS TO SECONDS, but usually the problem will specify with seconds, minutes, or heck, maybe even hours with LARGE half lives. So just read the question and dimensional analysis when necessary.
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