Learn: Changes of State and Energy Transfer (Particle Model)

Welcome!You've already explored states of matter and particle arrangement, so now we'll build on that by learning about how energy transfer causes changes of state. Let's dive in!

What Are Changes of State?Changes of state occur when a substance transitions between solid, liquid, and gas forms due to energy transfer. These processes include melting, freezing, boiling, condensing, and sublimation.

Energy Transfer During Change of StateEnergy transfer occurs when heat is absorbed or released. For example, melting requires particles to gain energy to overcome forces holding them together, while freezing releases energy as particles lose movement.

Latent HeatLatent heat is the energy required for a substance to change state without changing temperature. For example, during melting, energy is used to break bonds rather than increase temperature.

Specific Latent HeatSpecific latent heat is the energy needed to change 1 kg of a substance from one state to another at a constant temperature. It is different for melting and boiling.

Evaporation and BoilingEvaporation occurs when particles gain enough energy to escape from a liquid's surface, even below its boiling point. Boiling happens when all particles have enough energy to become gas at the boiling point.

Condensation and FreezingCondensation occurs when gas particles lose energy and become liquid. Freezing happens when liquid particles lose energy and solidify. Both processes release energy to the surroundings.

Review Time!Great work! You've learned about changes of state, energy transfer, and how particles behave during these processes. Let's review what you've learned with some final questions.