The Particle Model and States of Matter Matter exists in three fundamental states: solid, liquid, and gas. The particle model describes the arrangement and beha...
Matter exists in three fundamental states: solid, liquid, and gas. The particle model describes the arrangement and behavior of particles (atoms or molecules) in these different states.
In solids, particles are closely packed in a regular arrangement with strong forces holding them together. They vibrate around fixed positions but cannot move from their lattice sites, giving solids a definite shape and volume.
Liquid particles are randomly arranged and can slide past each other, allowing liquids to flow and take the shape of their container, but maintaining a relatively fixed volume. The particles have more energy than solids and move more freely.
Gas particles have the highest kinetic energy, moving rapidly in random directions and colliding frequently. Gases can completely fill any container, rapidly expanding to occupy the entire volume.
Density is the mass per unit volume of a substance. Particle arrangement affects density, with solids being denser than liquids, which are denser than gases due to the increasing space between particles.
Regular Solids: Density = Mass / Volume (measured or calculated)
Irregular Solids: Use displacement method (volume of water displaced)
Liquids: Use a density bottle (mass of liquid divided by bottle's volume)
Internal energy is the total kinetic and potential energy of particles in a substance. Heating increases internal energy, either raising the temperature or causing a change of state (melting, vaporization, etc.).
Specific heat capacity (c) is the energy required to raise 1 kg of a substance by 1°C. Specific latent heat (L) is the energy per unit mass to change state, e.g., E = mL for fusion or vaporization.
For a fixed mass of gas, pressure (P), volume (V), and temperature (T) are related. Increasing pressure or temperature raises particle kinetic energy and collision rate. Increasing volume reduces collision frequency. These relationships are described by gas laws (e.g., Boyle's Law, Charles's Law).