Before revision: Faster reactions are usually studied with ultrafast laser spectroscopy where utilization of femtosecond lasers allows short-lived transition states to be monitored at a time scaled down to a few femtoseconds.Atkins, p. 987 Evidence of a chemical change The following can indicate that a chemical change has taken place, although this evidence is not conclusive: Change of odor.
After revision: Faster reactions are usually studied with ultrafast laser spectroscopy where utilization of femtosecond lasers allows short-lived transition states to be monitored at a time scaled down to a few femtoseconds.Atkins, p. 987 Change of odor.