Molecular Interactions, Entropy, and Energy Lecture Notes

Vocabulary flashcards covering the concepts of gas expansion, diffusion, molecular interactions, and endothermic/exothermic thermodynamic processes based on lecture notes.

Spontaneous Expansion

The process where a non-interacting gas in a box spontaneously adjusts its volume to fill a vacuum once a partition is removed because the more disordered state is more likely.

Disorder

A state that is more likely to occur than an ordered state, driving the spontaneous expansion of molecules.

Diffusion

The process that spontaneously mixes labeled non-interacting molecules within a uniform material over time.

Inter-molecular Interactions

Attractions or repulsions between molecules that can cause spontaneous un-mixing in a solution.

Endothermic Process

A process, such as the dissolution of ammonium nitrate ($NH_4NO_3$), that absorbs heat energy ($Q$) from the surroundings, leading to an increase in both energy and entropy in the system.

Heat of Solution

The energy ($Q$) absorbed or released during a process like ammonium nitrate solid dissolving in water to form a liquid solution: $(NH_4NO_3)_z (H_2O)_m$.

Exothermic Process

A process, such as the crystallization of sodium acetate ($CH_3COONa$), that releases heat energy ($Q$) to the surroundings, leading to a decrease in both energy and entropy in the system.

Supersaturated Solution

A liquid solution state used in the crystallization of sodium acetate where lowering energy drives the reaction to form a saturated liquid solution and pure solid.

Entropy

A term associated with the level of disorder in a system.

Energy / Enthalpy

Thermodynamic properties that, along with entropy, influence whether a reaction or process will occur based on gains or losses to the surroundings.