Test: States Of Matter - Class 9 MCQ

According to kinetic theory og the gas molecule are in a state of constant rapid motion in all possible direction colloiding in a radom manner with one another and with the wall of the container and b/w two successive collisions molecules travel in a straight line path but show haphozard motion due to collisions. 

Fluidity is the ability of matter of not having a definite shape. Liquids such as water occupy the shape of the container in which they are kept that means they don't have a fix shape so they are called fluids. Gases are also considered fluids. 

Diffusion refers to the process by which different particles intermingle with each other as a result of their kinetic energy.

It is known as boiling. And that temperature known as boiling temperature. When you change a liquid in to gas this process is called vaporization. The process by which a substance gets converted from liquid to gas under low temperature or heating is called evaporation.

• In solids, particles are tightly packed together, resulting in minimal distance between them.
• This close arrangement is due to strong intermolecular forces, which hold the particles in fixed positions.
• In liquids, particles are still close but can move past each other, increasing the distance slightly.
• In gases, particles are far apart and move freely, leading to the greatest distance between them.

Layers of particles can slip and slide over each other  :
1. Liquid state is the fluid form of matter which can fill the lower part of the container.
2. Particles in liquid have little more inter molecular force than solids.
In liquid state particles  have little inter molecular space than solids. 
3. Hence,particles in liquid state  can vibrate , move about and slide past each other.

When we light an incense stick in one corner of room its fragrance spreads in the whole room because of the process involved DIFFUSION. It is because particles of matter are continuously moving in the air. Its particles vigorously spread and we can smell its fragrance in the whole room.

The least compressible state of matter is solid form. 

Solids have much more connected bonds or forces between their own atoms. Since their atoms are more tightly packed together, closer to one another, and are stronger bonds than liquids and gases, then they require more energy (more compression) to change the structure of their atoms. 

The molecules are continually colliding with each other and with the walls of the container. When a molecule collides with the wall, they exert small force on the wall The pressure exerted by the gas is due to the sum of all these collision forces.The more particles that hit the walls, the higher the pressure.

Humidity means moisture or water particles in the atmosphere. So when the Humidity in the atmosphere increases, the water content of atmosphere also increases. Though there is already water content in atmosphere, the wind speed is slowed down and the wet air can't evaporate in the same way as the evaporation takes place in dry weather.

At above critical temperature, substances are existing in gaseous state, since gas cannot be liquefied above it.

In gases particles are held by weak Van der waal forces. That is, the particles are moving far away from each other. 

Also, gases are more compressible than liquids whereas solids are in-compressible in nature. It is also known that Earth's atmosphere is surrounded by various gases.

Thus, we can conclude that gaseous state of matter is highly compressible, is made of particles moving independently of each other, and is present in large quantities near Earth’s surface.

The kinetic theory, particles of matter are in constant motion. The energy of motion is called kinetic energy.

The kinetic energy of particles of matter determines the state of matter. Particles of solids have the least kinetic energy and particles of gases have the most.

The rate of diffusion in liquids is faster than solids because in liquids molecules have a greater amount of space between them as compared to solids, or we can say they are less tightly packed. also, liquids can flow but solids cannot.

Volume of water remains the same when we add sugar to water because water have intermolecular spaces( the vacant space in between the particles of matter) between them in which the particles of sugar takes place.