Stars make the elements, but chemistry begins when those atoms share electrons, adopt geometry, vibrate collectively and cross reaction barriers. This lab follows one theme: the same atomic ingredients can produce different behavior when their structure and energy landscape change.
Move two atoms together. At long range they interact weakly; near an equilibrium separation attraction and repulsion balance; push them too close and the energy rises sharply.
Choose several familiar molecules. The arrows represent simplified bond-dipole vectors. Their vector sum can cancel or reinforce depending on molecular geometry.
Normal modes are collective coordinates: many atoms move together in a repeatable pattern. Explore three idealized modes of a linear triatomic molecule.
Change an activation barrier and temperature. Then switch on a catalyst. The endpoint free-energy difference stays fixed in this teaching picture while the barrier is lowered.
Structural isomers make emergence concrete: chemical identity is not determined by elemental inventory alone. Connectivity and three-dimensional arrangement matter.
C2H6O arranged as CH3-CH2-OH
C2H6O arranged as CH3-O-CH3