Oh, rate laws.
rate = - Δ[A] / Δt = k[A]
AKA rate = -d[A]/dt = k[A]
-d[A]/[A] = -kdt (?)
∫ -d[A]/[A] from [A0] to [At] = -k ∫ dt from 0 to t
ln [At] - ln [A0] = - kt
AKA ln ([At]/[A0]) = -kt or ln [At] = -kt + ln[A0]
Hell of a lot better than “just because,” Mr. Fab.
