I was reminded of this article by Michelle Francl[cite]10.1038\/nchem.1733[\/cite], where she poses the question “What anchor values would most benefit students as they seek to hone their chemical intuition?” She gives as common examples: room temperature is 298.17K (actually 300K, but perhaps her climate is warmer than that of the UK!), the length of a carbon-carbon single bond, the atomic masses of the more common elements.<\/p>\n
Well, one of my own personal favourites is anchoring chemical timescales. From 10-18<\/sup> s (that of electron dynamics, and presumably the fastest processes in chemistry) to 10+18<\/sup> (approximately the age of the universe). And (for a unimolecular process) this can be reduced to this equation:\u00a0\u00a0Ln(k\/T) = 23.76 – \u0394G<\/span>\u2021<\/sup>\/RT <\/span> I quoted this equation in a recent post<\/a>, since it gives you the fastest possible chemical reaction if\u00a0\u0394G\u2021 <\/sup> is set to zero (which of course is not a reaction but a vibration), but which gives you a good estimate of how fast a process will be for any given value of a barrier. It can of course also be solved for e.g.<\/em> the required barrier to achieve a half-life equivalent to the age of the universe.\u00a0<\/span>So, perhaps in increments of orders of 3 magnitudes (of which there are 13 covering the above span) would anyone like to contribute either:<\/p>\n