You physical states of matter are determined by the distance between molecules, molecular connections and kinetic energy that moves particles in a sample. Are they:
- solid;
- liquid;
- gaseous;
- plasma;
- Bose-Einstein condensate.
In solid state, we have well-assembled molecules with little movement. At the opposite extreme are the gaseous state it's the plasma, in which the molecules have a spacing between them and high kinetic energy. Materials in liquid state they are in the middle, have no defined physical form, have more kinetic energy than a solid material, and a smaller spacing between molecules than gaseous materials. O Bose-Einstein condensate is a relatively new discovery that revolves around the idea of having a sample with no movement between molecules, that is, no kinetic energy.
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Solid state
The molecules of a solid-state material connect with a sufficient force that results in defined format and volume. In this state we have little kinetic energy
between the particles and, although there is a small movement between them, it is not possible to visualize it macroscopically (with the naked eye).The shape of a solid can be changed when the material is under the action of a mechanical force (break, scratch, dent) or when there is a change in temperature and pressure. Each type of material has resistance to these impacts or to external changes, according to their nature.
Example
As an example, we can mention the gold, solid material at room temperature with a melting point of 1064.18 °C and a boiling point of 2855.85 °C.
liquid state
in the state liquid, there is no defined physical form, but there is defined volume, which prevents us from compressing the material significantly. The liquids have strength intermolecular weak, which allows you to manipulate and separate parts of a sample with ease. The force of attraction between molecules prevents them from moving freely like a gas. Furthermore, the surface tension (force of attraction between equal molecules) is what makes the formation of droplets possible.
Read too: Water surface tension - property resulting from hydrogen bonds
- Example
The most abundant and accessible example that we have of material in the liquid state under normal conditions of temperature and pressure is the Water, also considered a universal solvent.
gaseous state
A material in a gaseous state it has no defined shape or volume. It has a high expansion capacity due to the high kinetic energy. When placed in a container, the gas spreads indefinitely and, if under these conditions of confinement, the gas is heated, there will be an increase in kinetic energy and an increase in pressure of the system.
It is also worth noting the difference between gas and steam. Despite being in the same physical state, they have different natures. O steam, when placed under high pressure or by lowering the temperature, it returns to a liquid state. You gases, in turn, are substances that, under normal conditions, are already in the gaseous state and, in order to liquefy, it is necessary to have an increase in pressure and temperature simultaneously.
Know more:Difference between gas and steam
Example
An example of a gaseous substance is commonly found inside party balloons, the gas helium, which is a gáyou are noble and monoatomic (one atom molecule), being found in a gaseous state for normal conditions of temperature and pressure. THE density of helium is smaller than that of atmospheric air, which makes the balloons float.
Factors that determine physical states
What determines the physical state of matter is the organization of its molecules, the spacing between them and the kinetic energy (movement energy). Each element has a melting and boiling point that define the critical point, that is, where temperature and pressure the element maintains or changes its physical state. This critical point varies depending on the nature of the material. Furthermore, for each element, we have different intermolecular forces, which also influence the physical state.
Physical state changes
Possible changes in physical state occur with changes in temperature and pressure. See what they are:
- Fusion: transition from solid state to liquid state through heating.
- Vaporization: transition from liquid to gaseous state. This process can happen in three different ways:
Boiling: The change from a liquid to a gaseous state happens by heating the system evenly, as in the case of a kettle where some of the water evaporates as you heat up.
Heating: The change from liquid to gaseous state happens suddenly, as the material undergoes a rapid and significant change in temperature. An example is when the drop of water falls on a hot plate.
Evaporation: The change takes place gradually, as only the liquid's contact surface with the rest of the system evaporates. Example: drying clothes on the clothesline.
- Condensation or liquefaction: passage from the gaseous state to the liquid state by means of cooling.
- Solidification: occurs when the temperature is further reduced, resulting in freezing, that is, passage from a liquid to a solid state.
- Sublimation: is the transition from solid to gaseous state without going through the liquid state. This process takes place when the substance has a high melting point and high vapor pressure. Example: dry ice and mothballs.
Note: The same term or resublimation is used for the inverse process (passage from the gaseous to the solid state).
other physical states
In 1932, Irving Langmuir, in the Nobel Prize of Chemistry, added the term plasma to a condition of matter that had been studied since 1879. It is a physical state in which the particles are highly energized, have a distance between them and little or no connection between the molecules. These properties are quite similar to the gaseous state, except that the kinetic energy of a plasma is much greater than that of a gas.
This kind of condition of matter not common in terrestrial nature, however it is abundant in the Universe, as stars are basically balls of plasma at high temperatures. Artificially it is already possible to manipulate and add value to the plasma, which is even commercially used in plasma TVs, fluorescent lamps, LED conductors, among others.
In 1995, the çBose-Einstein waveit was established as a physical state of matter. Eric Cornell and Carl Weiman, using magnets and lasers, cooled a sample of rubidium, an alkali metal, until the energy between the particles was close to zero. Experimentally, it was noticed that the particles united, ceasing to be several atoms and starting to behave in unity, as a "superatom".
Bose-Einstein condensate has characteristics of a superfluid (fluid without viscosity and high electrical conductivity) and has been used in quantum studies to investigate black holes and the wave-particle paradox.
Read too: Difference between fluorescence and incandescent lamps
solved exercises
question 1- (Fabove)Watch:
I – A mothball stone left in the closet.
II – A container of water left in the freezer.
III- A bowl of water left in the fire.
IV – The melting of a piece of lead when heated.
These facts are correctly related to the following phenomena:
THERE. Sublimation; II. Solidification; III. Evaporation; IV. Fusion.
B) I. Sublimation; II. Sublimation; III. Evaporation; IV. Solidification.
C) I. Fusion; II. Sublimation; III. Evaporation; IV. Solidification.
D) I. Evaporation; II. Solidification; III. Fusion; IV. Sublimation.
HEY. Evaporation; II. Sublimation; III. Fusion; IV. Solidification.
Resolution
Alternative A.
I – Sublimation: Mothballs is a non-polar compound with a very high boiling point. This compound goes from a solid to a gaseous state without going through a liquid state.
II – Solidification: Water subjected to a low freezer temperature freezes, which chemically we call solidification, which is the passage from the liquid state to the solid state.
III – Evaporation: The water left in a container on fire undergoes an increase in temperature. The boiling point of water is 100°C, so when the system reaches this temperature, it will begin to evaporate, changing from a liquid to a solid state.
IV – Melting: Lead has a melting point of 327.5°C, which is a relatively high temperature; however, lead melting is a common process in industries, which is nothing more than the transition from solid to liquid state.
Question 2 - (Mackenzie-SP)
By analyzing the data in the table, measured at 1 atm, we can say that, at a temperature of 40 °C and 1 atm:
A) ether and ethanol are in the gas phase.
B) ether is in the gas phase, and ethanol is in the liquid phase.
C) both are in the liquid phase.
D) ether is in the liquid phase, and ethanol is in the gas phase.
E) both are in the solid phase.
Resolution
Alternative B. If the boiling point is the point at which the substance changes into a gaseous state, ethanol at 40°C will still be in a liquid state. Ether has a lower boiling point, which is 34°C, so at 40°C it will be in a gaseous state.
Question3 – (Unicamp)Icebergs float in seawater, just like ice in a glass of drinking water. Imagine the initial situation of a glass of water and ice, in thermal equilibrium at a temperature of 0°C. Over time, the ice melts. As long as there is ice, the system temperature
A) remains constant but system volume increases.
B) remains constant but system volume decreases.
C) decreases and system volume increases.
D) decreases, as does the system volume.
Resolution
Alternative B. The temperature remains constant until the iceberg melts completely, as there is a heat exchange in search of thermal equilibrium between the two phases of matter. Water is one of the few elements that admit different density for different physical states of the same compound.
Visually we can see that the ice density is lower. In the case of the iceberg and in a glass of water and ice, the ice stays on the surface. This happens because, when water is frozen, in the ice formation process, it gains volume, but the mass remains the same as when it was water in a liquid state. Therefore, when the iceberg melts, the volume of the system decreases.
By Laysa Bernardes Marques de Araújo
Chemistry teacher
Source: Brazil School - https://brasilescola.uol.com.br/quimica/estados-fisicos-materia.htm