Phase Changes: Learn Meaning, Examples, and Characteristics

Phase Change is the physical process of transition between one state of a medium into other. It is identifiable by specific parameters, or with different values of the parameters. The term “phase change” is frequently used to describe changes in the three fundamental states of matter; solid, liquid, gas, and in rare instances plasma as well. 

In this Chemistry article, learn about Phase Change, different types and characteristics. 

Phase Change Of Matter

Phase Change are physical transformations of a substance from one phase to another. The transformation typically takes place at a specific temperature, also referred to as the substance's melting or boiling point, when heat is applied or removed.

When a substance gains or loses energy, molecules or atoms either move closer together or farther apart, causing a phase transition. A solid turns into a liquid when it has enough energy. A liquid can turn into a gas by gaining a significant amount of energy. 

An energy depleted gas transforms into a liquid. Similarly, a liquid turns into a solid when its energy is lost. Sometimes a solid obtains so much energy that it skips the liquid phase and goes straight to the gas phase which is also known as sublimation. 

The image below represents the Phase Change Diagram. 

Along with the concept of Phase Change, also learn about Difference between Organic and Inorganic Compounds here. 

Boiling

When a liquid is heated to its boiling point, it undergoes a process known as boiling in which vapours of that liquid or substance are produced. When the liquid's vapour pressure equals the air pressure acting on it, the liquid transitions from a liquid phase to a gaseous phase. Since boiling is a physical transformation, molecules are not chemically changed. This phase transition process is used in cooking, boiling liquids to kill germs, purifying water, etc. 

Along with the concept of Phase Change Examples, also learn about Difference between Pure substance and Mixture here.

Condensation

Condensation is the transition of a substance from its gaseous state into its liquid state. The process is referred to as the reverse of vaporization. It can also be described as the transformation of water vapour into liquid water when it comes into contact with a liquid or solid surface in the atmosphere.

Condensation is an integral component of the distillation process. The solvent and solute can be separated from a solution with the help of condensation. The solvent evaporates as a result of heating the solution and the solvent is subsequently separated during condensation. The most commonly observed example of condensation is the appearance of water droplets on plant leaves early in the morning and the collection of water droplets over the cover or lid of a dish keeping the hot substance inside.

The image above represents the condensation phase change. 

Along with the concept of Phase Change, also learn about Michael Addition Mechanism here. 

Deposition

When a gas changes into a solid without first transitioning to the liquid phase, this is referred to as deposition. The deposition is sometimes referred to as desublimation because sublimation is the opposite of deposition. 

The soot layer on chimney walls is evidence of deposition. Gas particles that are released during the burning of carbon-based materials collect as soot inside the chimney. The heat inside the chimney prevents substances from being in a liquid state. The energy from the gas is absorbed by the brick as the carbon vapour strikes the side of the chimney, causing the gas to solidify.

Along with the concept of Examples of Phase Change in Daily Life, also learn about Ammonium Bromide Formula here. 

Evaporation

When a liquid transitions from the liquid phase to the gas phase, evaporation takes place on the liquid's surface. High concentrations of the evaporating substance in the surrounding gas considerably slow down evaporation, as is the case when humidity impacts the rate of water evaporation. Depending on the collision between the vapour particles, the liquid's molecules exchange energy when they come into contact. A molecule at the surface will escape and turn into a gas when it has enough energy to outpace the vapour pressure. When evaporation happens, the energy taken from the vaporised liquid will drop the temperature of the liquid, resulting in evaporative cooling.

Along with the concept of Phase Change, also learn about Ammonium Nitrite Formula here. 

Heating

Metals undergo structural, magnetic, and electrical changes upon heating. When heated, the metal enlarges. It grows in length, volume, and surface area which is known as Thermal expansion. Different metals exhibit different degrees of thermal expansion. When constructing metallic structures like home plumbing and fixtures, this method is quite helpful. 

Along with the concept of Phase Change of Matter, Also learn about Bond Strength here.

Freezing

The process of freezing converts a substance's physical state from liquid to solid. When the temperature is reduced to a liquid's freezing point, the phase change process occurs. As it reduces bacterial development and degradation, this procedure is used to preserve fruits and vegetables (frozen food) as well as animal specimens in laboratories.

The image above represents Gas to Ice Phase Change.

Along with the concept of Gas to Ice Phase Change, also learn about Energy of Orbitals here. 

Melting 

A physical process called melting or fusing causes a substance to change its phase from a solid to a liquid. This happens when the solid's internal energy rises, usually as a result of the application of heat or pressure, which raises the material's temperature to the melting point.

Example of Melting Phase Change: Ice to water. 

The image above is an Example of Melting Phase Change. It represents the melting of ice into water. 

Along with the concept of Phase Change, also learn about Integrated Rate Equation here.

Sublimation

Sublimation is the direct transfer of a substance from solid to gas without passing through the liquid state. In a substance's phase diagram, the triple point, or the lowest pressure at which the substance may exist as a liquid, corresponds to a process called sublimation, which is endothermic and takes place at temperatures and pressures below those values.

Along with the concept of Phase Change, also learn about Solute vs Solvent here. 

Characteristics of Phase Change

Some of the most common characteristics of phase change are discussed as follows

• Monitoring a material's temperature while it is heated or cooled can reveal a phase transition.
• The temperature of a substance does not change during a phase change.
• Each of the two states that a material can be in at one time is referred to as a phase. For instance, an iceberg in the water has a solid phase and a liquid phase.
• During a phase change, energy is transferred between a material and its surroundings. The direction of the transfer is determined by the phase transition. Therefore, energy is either absorbed or released during a phase change.
• A substance experiences a known reversible physical change when it transitions from one state of matter to another.

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