Matter and Different States of Matter - NCERT Solutions For Class 9
Matter and Different States of Matter – NCERT Solutions For Class 9
What is Matter?
Everything around us, the entire cosmos, the whole universe, everything is made of Matter.
Matter Definition: Any substance that occupies space and inherits mass is called Matter. However, some exceptions are electricity, heat, magnetism, vacuum, silhouette, and light and audio energy, as these have no mass and do not occupy a space. Matter consists of very tiny minuscule particles called atoms.
Structure & Characteristics of Matter
Matter consists of really tiny particles called molecules.
These molecules have some space between them which are known as Intermolecular spaces.
These molecules tend to move because they have Kinetic Energy.
Kinetic energy is a type of energy that objects in motion possess. It is, in essence, the energy of mass in motion.
Molecules consist of atoms. Atoms are the most fundamental unit of Matter.
Atoms further have subatomic particles which contain different types of charges. The subatomic particles are –
Protons – Positive charge
Electrons – Negative charge
Neutrons – No charge
Molecules of a substance attract each other. The pull depends on the distance between the particles that are called intermolecular spaces.
The more distance between the particles, the weaker the pull between molecules gets.
States of Matter
Matter can get classified into five states – solids, liquids, gases, plasma, and the Bose-Einstein condensate.
There were only three states known to man for the longest time – Solids, liquids, and gases. Therefore, these three states are the most commonly mentioned states of Matter.
Solids have very tightly bound molecules. Therefore, the molecules have a strong pull. As such, solid-state has a distinct form and volume.
Another feature of this form is its high boiling point and high density. When a force gets applied to it, the particles only vibrate in the direction of their current location.
Because there is minimal intermolecular space, the kinetic energy to disperse the particles is weak.
They cannot be compressed and cannot flow due to their high density.
Liquids have a weaker molecular force in comparison to Solids. Therefore, the molecules have higher kinetic energy in this state and move around more freely.
Because of this property, liquids have a fixed volume but no fixed form. When poured into a container, Liquids take on the shape of the container. They do not breach the liquid form’s boundary.
There is a larger space between the atoms, allowing them to be compressed and flow.
This state has a low density, as well as a low boiling and melting temperature.
Gases have an even more weak molecular force than Liquids. Therefore, the molecules have tremendous kinetic energy in this state.
Therefore, they have no set shape or volume because of their vast intermolecular space.
Their density is lower than that of a solid or liquid state.
They exert stress on the container’s internal surface as they disperse. This force is known as pressure. Pressure gets calculated using a variety of units, including Pascal (Pa) and pounds per square inch (psi).
The fourth form of Matter, Plasma, is similar to the gaseous state. This form, like gases, has no defined shape or volume and has a lower density than solids or liquids.
Plasma is a state in which atoms strip away their electrons at extremely high temperatures, leaving +ve charged subatomic particles known as Ions.
Gases get formed by neutral molecules with an equal amount of –ve and +ve charged electrons and protons. On the contrary, Plasma is a charged gas in which atoms receive or lose electrons, causing them to become positively or negatively charged. This process is known as ionisation.
Plasma is present in celestial bodies such as the sun and stars, owing to their high temperatures.
5. Bose-Einstein Condensate (BEC)
The Indian scientist Satyandra Nath Bose proposed the concept of BEC in 1920. 4 years later, Albert Einstein formulated this theory and named it the Bose-Einstein condensate.
BEC is created by freezing extremely low-density gas at a temperature near absolute zero. The temperature at absolute zero is 0 Kelvin, or -273.15 degrees Celsius, or -460 degrees Fahrenheit.
However, it is not feasible to attain this temperature. But it is possible to come close by employing laser cooling technology.
At this temperature, the atoms cease to move because they lack the kinetic energy to do so.
Therefore, the atoms start to clump together and enter the same energy state. They become physically indistinguishable and begin to behave like a single atom.
Examples – Superfluids, Superconductors.
When energy is supplied or removed from a particular state of Matter, it can shift from one state to another. When the temperature changes, the conditions of Matter can change.
In general, as the temperature rises, molecules become more active.
The transfer of particles from a higher concentration area to a lower concentration area is diffusion. All substances, whether solid, liquid, or gas, can disperse. Therefore, diffusion takes place in any of the three major physical states. The rate of diffusion gets determined by the nature of the interaction between the substance and the medium.
In gas, diffusion is rapid; lighter gases diffuse faster than denser ones. Gases spread swiftly in air, slowly in liquid, and slowly still in solids.
Now that we know so much about matter, let’s understand its application by tracing examples around us. To get a perspective of this concept, check out the video below.
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