Change States

Change in State Definition

In the field of physics, the matter can exist in distinct forms or states in the universe. However, there are only the primary four fundamental states of matter solid, liquid, gas, and plasma. We observe these matters every day around us in our lives. For instance, water exists in various states around us, such as it exists as water vapour in the gaseous state, ice in the solid-state, and water in the liquid state. In addition to that, there are several other intermediate states of matter such as liquid crystal, glass, quark-gluon plasma etc. that can only exist due to harsh conditions such as increased temperature, high pressure, extreme density and high energy. The different states of process exhibit different or change in the properties. Going further let us study the change in state definition and different states of process in depth.   


States of Matter

As we already know, the four fundamental states of matter are solid, liquid, gas, and plasma. Solids exhibit tightly packed constituent particles or atoms or molecules. The movement of the particle is restricted due to a strong force between them that only enables them to vibrate. This movement results in the solids having a specific volume and specific shape. It is impossible to change its structure. They only change structure when an external force is applied, for instance, breaking or cutting. Liquid has a fluid tendency that is mostly incompressible. They retain a specific volume; however, they take the shape of their container. If the external pressure and temperature remain constant, then the size won’t change. The existence of liquids depends upon the maximum temperature called critical temperature. 

In addition to that, gases are compressible fluids. Unlike solids and liquids, gases can expand to fill their container and take the shape of the box. The gas molecules have adequate kinetic energy to minimize the effect of intermolecular forces. Also, the distance between the adjacent molecules of a gas is way higher than the size of the molecule. Gases do not have a fixed volume or shape. Similar to gas plasma do not have a fixed volume or shape. The main difference is that plasmas are strongly conducive to electricity and can produce currents, magnetic fields, electromagnetic forces etc. Let us look at the change in state definition and an example of Change in State in Chemical reaction.


Change in State

Matter can transition from one state to another under certain conditions. The main requirement is the application of temperature and pressure. Let us look at the change in states for the three most common matter solid, liquid, and gas.

  • Solid to Liquid or Liquid to Solid:- Solids can change their state to liquid state when the temperature is increased. On increasing the temperature, the kinetic energy of the particles also increases. And with that, as the energy rises, the particles start vibrating with much higher frequency than before. Hence, the attractive forces between particles start decreasing. That results in the particles detaching themselves from their fixed positions and starts moving in a free manner. Subsequently the solid goes through a phase transition and becomes a liquid. This phenomenon is referred to as melting, and the temperature at which this process occurs is called the melting point. Similarly, when the temperature is reduced in case of liquids (example below zero degree celsius for water). Hence, liquids go through a phase transition to become solids, and the process is referred to as freezing. The temperature at which this process occurs is called the freezing point.

  • Liquid to Gas or Gas to Liquid:- when the temperature is increased for liquids (heat) their particles start to move at increased speeds. The energy supplied due to the temperature enables the particles of liquid to overcome the force of attraction. It ultimately leads them to go through a phase change and transition into a gas (vapour). The process is called evaporation, and this temperature is referred to as the boiling point. For instance, when we boil the water at high temperatures, it starts evaporating from the container. Similarly, gases can change their phase into the liquid state by the process of condensation.

  • Gas to Solid or Solid to Gas:- The process that leads the transition of solid to a gas is known as sublimation. One typical example of this phenomenon is dry ice or solid carbon dioxide. At room temperatures, it turns into a gas. When a gas becomes a solid by skipping the liquid state, then that process is called deposition. Let us look at the Example of Change in State in Chemical Reaction.

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                                            (Change in states of matter)

FAQ (Frequently Asked Questions)

1. What Are Liquid Crystal States?

According to the change in state definition, a matter can change its states depending upon certain conditions. The temperature and pressure play a crucial role in this process. The state of matter that contains the properties between the ordered solids and liquid is known as liquid crystal states. Commonly they show long-range order while able to have fluidity like liquids. There are three types of phases in liquid crystals namely Metallotropic, lyotropic, and thermotropic. Liquid crystals are made up of both inorganic molecules and organic molecules. Hence, their transition also depends upon the organic and inorganic ration aside from concentration and temperature.

2. What Are Some Less Familiar States Of Matter?

Aside from the four original states, there are several intermediate states as well. Some of them are non-classical states such as crystals, magnetically-ordered, glass etc. Some are low-temperature states such as superfluids, dropleton, photonic matter, rydberg molecule, fermionic condensate etc. Including the listed ones, there are still many different intermediate states. A process or a chemical reaction sometimes leads the reactants involved in the process to change states. One great example of change in state in chemical reaction is the reaction of hydrogen gas and chlorine gas to form hydrogen chloride, which is a liquid.

H2 + Cl2 ---> 2HCl