Gas Laws and States of Matter Fundamentals

Gas Laws and Constant Variables

Constant Temperature: Boyle's Law

If the temperature remains constant, increasing the pressure on a gas decreases the volume it occupies. This occurs because the number of collisions per unit surface area increases.

Constant Pressure: Charles's Law

If the pressure on a gas is constant, a rise in temperature causes an increase in the volume it occupies. This is due to the particles having higher kinetic energy and therefore moving faster, causing more frequent collisions.

Constant Volume: Gay-Lussac's Law

If the volume occupied by a gas remains constant, an increase in temperature causes an increase in the pressure of the gas. This is because increasing the temperature increases the kinetic energy of the particles, causing an increase in the number of collisions that occur.

Phase Changes: Liquid to Gas

The transition from a liquid to a gas can occur from the surface of the liquid (evaporation) or affect the entire mass (boiling). The boiling temperature depends on atmospheric pressure. Thus, at lower pressure, it is easier for fluid particles to transition to the gas phase.

Characteristics of the Liquid State

In the liquid state, the kinetic energy of the particles is sufficient to allow movement such as vibration, rotation, and translation, but it is not enough to separate them from each other as happens in the gaseous state. A liquid is a fluid without a definite shape but with a constant volume. As the temperature increases, the kinetic energy of the particles causes them to separate slightly, increasing the volume. When the energy is great enough to overcome attractive forces, particles escape the fluid.

Characteristics of the Solid State

The internal order in solids can be reflected in their external form. These substances may be limited by flat faces that form polyhedra (crystalline solids) because they possess an internal crystalline structure. Some may not externally present a polyhedral shape despite their internal structure. There are also substances such as glass and plastics, known as amorphous solids, which have neither a defined structure nor a crystalline form. Currently, these substances are often considered highly viscous liquids.