9.1.2 States of Matter
This is the second lecture from Chapter 1: ‘States of Matter and Phase Changes’ of the new book for 9th Class Chemistry (Punjab Board – PCTB). It discusses the four common states of matter, i.e., solid, liquid, gas, and plasma. It also provides a basic idea of intermediate states of matter and exotic states of matter. The lecture includes a multiple-choice quiz, short-answer questions, and detailed long-answer notes.
MCQs Based Quiz
Short Questions
How would you define matter?
Anything other than energy that has mass and occupies volume is called matter. We are made of matter. The food that we eat is also a matter. In other words, matter is everywhere around us.
What do you mean by the state of matter?
A state of matter is one of the distinct forms in which matter can exist. In each state, the particles of matter behave in a similar way. There are four common states of matter: solid, liquid, gas, and plasma.
How do the different states of matter differ from each other?
The states of matter differ from each other due to differences in the strength of intermolecular forces, the arrangement of particles, and the distance between them.
Write at least two properties of the gaseous state of matter.
(Write any two of the following):
Gases have very weak intermolecular forces.
Their particles are very far apart and have no specific arrangement.
They are easily compressible.
They have very low densities.
Write at least two properties of the liquid state of matter.
(Write any two of the following):
In liquids, particles are closely packed but can move randomly.
They have stronger intermolecular forces as compared to gases.
They are not compressible.
They have higher density that gases.
Write at least two properties of the solid state of matter.
(Write any two of the following):
Solids have highest intermolecular forces.
Particles of solid have only vibratory motion.
Crystalline solids have the perfect arrangement of particles.
Therefore, they are almost incompressible.
Solids have the highest densities among the four common states of matter.
Why are crystalline solids the hardest substances?
Crystalline solids are the hardest substances because their particles are strongly bonded and perfectly arranged.
How would you define plasma?
Plasma is composed of high kinetic energy particles. It is a partially ionized gas containing electrons, ions, and photons.
What is an intermediate state of matter?
An intermediate state of matter is a state that exists between two distinct states and has properties of both. For example, the intermediate state between a gas and a liquid is called a supercritical fluid.
How would you define supercritical fluids?
A supercritical fluid is an intermediate state that exists between liquid and gaseous state and has properties of both.
What is the importance of supercritical fluids?
Supercritical fluids such as supercritical CO2 can be used to carry out reactions that can not be carried out in normal liquid solvents.
What is a liquid crystal?
A liquid crystal is a state of matter whose properties are between those of conventional liquids and crystalline solids.
Where are liquid crystals commonly used?
They are used in display devices such as computer monitors, clocks, watches, and navigation systems.
What is graphene?
Graphene is a two-dimensional crystal consisting of a single layer of carbon atoms arranged in a hexagonal pattern.
What are the properties of graphene?
Graphene is tough, flexible, light, and has high resistance.
What are the exotic states of matter?
Exotic states of matter are those states of matter which are not commonly encountered
Give some examples of exotic states of matter.
Examples of exotic states of matter include dark matter, Bose-Einstein condensate, nuclear matter, and quantum spin liquid.
Descriptive Question
1. Write a detailed note on four common states of matter.
Matter:
This universe is made up of matter and energy. Anything that has mass and occupies volume is called matter. Everything else that is not matter is called energy.
Matter is all around us and based on its properties we classify it into different states.
States of Matter:
A state of matter is one of its many distinct forms in which matter can exist. In each state, the particles of matter behave in a similar way. These particles attract each other through intermolecular forces.
There are four common states of matter:
- Solid
- Liquid
- Gas
- Plasma
However, matter can also exist in some other unique states, such as intermediate states and exotic states.
These states of matter differ from one another due to differences in:
- The strength of intermolecular forces
- The arrangement of particles.
- The distance between particles.
Solid State:
The solid state of matter has the following properties:
- It has strong intermolecular or interatomic forces.
- Its particles are fixed at their positions and closely packed.
- They only have vibratory motion.
- In crystalline solids, these particles are perfectly arranged and tightly bonded.
- Solids have a definite shape and fixed volume.
- They do not need a container for storage.
- They are relatively incompressible and hard.
- Crystalline solids are very incompressible and hard.
- Due to the close packing of particles, solids have very high density.
- Crystalline solids are the most dense substances.
Liquid State:
The liquid state of matter has the following properties:
- Liquids have moderate intermolecular forces.
- Their particles are closely attached but can move freely.
- Due to this close packing of particles, liquids are incompressible.
- They do not have definite shape but have a fixed volume.
- They can only be stored inside a container.
- They have moderate densities, higher than gases but lower than solids.
Gaseous State:
The gaseous state of matter has the following properties:
- Gases have very weak intermolecular forces.
- Their particles are very widely apart.
- These particles move randomly.
- Due to large distances between particles, gases are highly compressible.
- They can only be stored in a closed container.
- They have very low densities.
Plasma State:
Plasma is a state of matter that is composed of partially ionized gas particles, electrons, ions and photons. These particles have very high kinetic energy.
Plasma is found in fluorescent tubes, lightning and welding arcs.
2. Write a note on the intermediate states of matter as well as the exotic states of matter.
Intermediate States of Matter:
States of matter that have properties of two different states are called an intermediate state of matter.
Examples: Supercritical fluids, liquid crystals and graphene.
Supercritical Fluid:
Supercritical fluids are a highly compressed state of matter which show properties of both gases and liquids.
Supercritical fluids differ from common liquids because they can carry out reactions that are not possible with ordinary liquid solvents.
Liquid Crystal:
Liquid crystal is a state of matter that have properties of both liquids and crystalline solids.
They are used in computer monitors, clocks, watches and navigation systems.
Graphene:
Graphene is a two-dimensional crystal which is composed of a single layer of carbon atoms arranged in a hexagonal pattern.
It is a tough, flexible and light material that has a very high resistance.
Exotic States of Matter:
States of matter that are very rare and uncommon are called exotic states of matter:
Examples: Dark matter, Bose-Einstein condensate, nuclear matter, quantum spin liquids and many other.