If we looked through a very strong microscope, how do the solid, liquid and gas states differ?
The diagrams give a snapshot of a very small sample of matter that is composed of blue particles. The particles could be individual atoms, but more commonly they consist of several atoms joined by chemical bonds (as in H2O).
The solid form has a regular arrangement of the particles where they are all stacked neatly.
In the liquid the arrangement of the particles is more random. In the gas the particles are farther apart.
What happens to the particles when a state change occurs?
What does the added energy do?
When heat energy is supplied at the melting temperature, the particles move faster and the solid melts to form a liquid which has a more random arrangement of the SAME particles.
When additional heat energy is supplied the blue particles move even faster and become separated from one another to form the gas that fills the entire volume of the vessel.
Evaporation and sublimation involves particles at the surface acquiring sufficient energy from a source of heat (like the sun) to escape from the surface.
Boiling occurs when all blue particles (including those in the middle of the liquid) have sufficient energy to escape into the gas phase.
The diagram shows that these phase changes do NOT result in a change in the nature of the particles. Thus if the particles are composed of several atoms bonded together, there is no decomposition to simpler particles.
The diagrams give a snapshot of a very small sample of matter that is composed of blue particles. The particles could be individual atoms, but more commonly they consist of several atoms joined by chemical bonds (as in H2O).
The solid form has a regular arrangement of the particles where they are all stacked neatly.
While particles in a solid are in motion, the extent of their movement is very limited.
In the liquid the arrangement of the particles is more random. In the gas the particles are farther apart.
increasing energy  | ||
 model of solid | melts freezes |  model of liquid |
| increasing energy | |
| vaporises condenses |  model of gas |
What happens to the particles when a state change occurs?
What does the added energy do?
When heat energy is supplied at the melting temperature, the particles move faster and the solid melts to form a liquid which has a more random arrangement of the SAME particles.
Particles in the liquid are moving faster than particles in the solid.
BUT the particles have the same composition in the liquid as in the solid.
If energy is removed from the liquid, the liquid becomes solid
BUT the particles have the same composition in the liquid as in the solid.
If energy is removed from the liquid, the liquid becomes solid
When additional heat energy is supplied the blue particles move even faster and become separated from one another to form the gas that fills the entire volume of the vessel.
Evaporation and sublimation involves particles at the surface acquiring sufficient energy from a source of heat (like the sun) to escape from the surface.
Evaporation of a liquid may occur at temperatures below the boiling temperature if the liquid is in a container that is open so that the gas can escape.
Boiling occurs when all blue particles (including those in the middle of the liquid) have sufficient energy to escape into the gas phase.
The diagram shows that these phase changes do NOT result in a change in the nature of the particles. Thus if the particles are composed of several atoms bonded together, there is no decomposition to simpler particles.