All substances have internal energy (chemical potential + kinetic energy) due to the motion and separation of their particles
All particles are in constant motion and collide elastically to transfer kinetic energy
3 Chemical States of matter
Solid: Particles arranged in a fixed lattice, i.e. have fixed volume and shape (all strong bonding, i.e. ionic, metallic covalent)
Minimal movement of particles
Liquids: Bonds are attractive enough to keep particles in the substance, but particles can move past each other, i.e. continual making and breaking of bonds, thus fixed volume but no fixed shape
Moderate movement of particles
Gases: No attraction between particles, no fixed volume or space, will “fill” every container they are put in
High amount of movement of particles
Absolute Zero
Temperature is a measure of the average kinetic energy of a substance
Absolute zero occurs when there is no internal energy in a substance
This is impossible, due to chemical potential energy, and all particles having some form of kinetic energy
State Changes
A change of state occurs at a constant specific temperature (i.e. the kinetic energy of particles stays constant) and the heat energy added/removed is only to overcome the cohesion forces/establish the cohesion forces between particles
Fusion
Refers to the state transition process by which solids transition to a liquid.
Here, heat is transferred into the solid from the surrounding at the freezing point
The heat added is used to overcome the cohesion forces between solid particles
After this is achieved, the particles can undergo translational motion (i.e. the substance is a liquid now), and so further addition of heat simply increases the kinetic energy of the particles and thus increases their temperature
Freezing
Refers to the state transition process where a liquid transitions to a solid
Here, heat is transferred out of the solid to the surroundings at the freezing point
The heat removed allows the particles to establish cohesion forces
After this is achieved, the particles can no longer undergo translational motion (i.e. it is not a liquid), and are restricted to vibrational and rotational motion (i.e. now exist as solids)
Further removal of heat simply degreases the average kinetic energy of the particles, and thus decreases their temperature
Vaporisation/boiling
Refers to the state transition process where a liquid transitions to a gas
Here, heat is transferred into the solid from the surrounding at the boiling point of the liquid
The heat added is used to overcome the cohesion forces between liquid particles
After this is achieved, the particles can undergo unrestricted random Brownian motion (i.e. the substance is a gas now) and so further addition of heat simply increases the average kinetic energy of the particles, and thus increases their temperature
Condensation
Refers to the state transition process where a gas transitions to a liquid
Here, heat is transferred out from the gas to the surrounding at the boiling point of the liquid
The heat removed causes cohesion forces to be established between the gas particles
After this is achieved, the particles can no longer undergo restricted random Brownian motion (no longer gas) and are restricted to vibrational and translational motion (liquid)
Thus, further removal of heat simply decreases the average kinetic energy of the particles and thus decreases their temperature