States of Matter Quiz

Study Notes

Matter exists in three states: solid, liquid, and gas (or vapor)
The state of matter is determined by the internal energy or characteristic temperature.
Solids exist at low temperatures below their solidification temperatures.
When solids are heated, their atoms vibrate and eventually de-bond converting the solid to liquid.
The thermal energy required to break the solid structure is called the latent heat of fusion.
The latent heat of fusion is the same energy required to convert a solid to liquid or vice versa, at the normal melting temperature and pressure.
Liquids can be converted to vapor at the normal pressure and boiling point.
The heat required to convert one gram of liquid to vapor is known as the latent heat of vaporisation.
Vapor heated above its critical temperature becomes a gas. It cannot be liquefied by pressure above this temperature.
At very high temperatures, the electrons in matter reach the plasma state.
Matter transitions between the states with the application of heat or cooling.

Dental materials can be broadly classified based on their interatomic bonding energies, crystal lattice structures, and composition.
Different bonding energies, crystal lattice structures, and compositions contribute to the varied properties of different material groups.

The crystal structure of a material can affect its physical properties.
Different crystal structures, like FCC, BCC, and HCP, can be produced by the combination of elements, and also by heat treatments.
Crystals like gold alloy castings can undergo precipitation heat treatment, which can result in lattice inhomogeneity and increased strength.
Changes in allotropic forms at certain temperatures can cause changes in mechanical properties.
Sudden cooling of Austenite (FCC) steel produces hard martensitic steel with a distorted FCT structure.
The mechanical properties of α -Ti (HCP) change when heated above 885°C, transforming it to β -Ti (BCC).
The β -Ti has more desirable properties for orthodontic appliances, and the β (BCC) structure can be retained by alloying with aluminum and vanadium.
Superelasticity and shape memory effects of Ni-Ti alloys are due to changes in their lattice structures induced by temperature or stress, followed by recovery to the original structure through twinning.

Many dental materials like waxes, resins, composite resins, glass-ceramics, etc. are non-crystalline.

The melting point decreases and the boiling point increases at higher pressures.
The boiling point of MMA monomer during the curing of dentures in a flask under high pressure may be higher than 100.8°C (the normal boiling point). This can influence the formation of monomer porosity in dentures.
Latent heats of fusion and vaporisation for water are 80 cal per gram at 0°C and 540 cal per gram at 100°C, respectively.
Large amounts of heat are absorbed during melting and released during solidification, affecting casting, brazing, and welding processes.