Calorimetry: Calorimetry is a technique used to measure the heat absorbed or released during a chemical reaction. By measuring the temperature change of a system (usually in a device called a calorimeter) during a reaction, one can calculate the heat energy involved. This helps determine the enthalpy change (∆H) of the reaction, which is a measure of the energy change.

Spectroscopy: Spectroscopic techniques, such as infrared spectroscopy (IR), nuclear magnetic resonance spectroscopy (NMR), and UV-Vis spectroscopy, can provide information about the energy levels of molecules. For instance, IR spectroscopy measures the vibrational energy levels of molecules, while NMR spectroscopy provides information about the magnetic properties of nuclei in molecules.