Matter in Our Surroundings – Key Concepts

Fill-in-the-blank flashcards covering definitions, properties, state changes and key units from the NCERT chapter "Matter in Our Surroundings."

Anything that occupies space and has mass is called __.

matter

Early Indian philosophers proposed that all matter is composed of five elements known as the __.

Panch Tatva (air, earth, fire, sky, water)

Modern scientists classify matter on the basis of __ properties and chemical nature.

physical

The smallest unit of matter discussed in this chapter is referred to as a __ of matter.

particle

When sugar dissolves in water, its particles occupy the __ between water particles.

spaces

Just a few crystals of potassium permanganate can colour a large volume of water, proving that particles are extremely __.

small

Particles of matter possess continuous random motion, a form of energy called __ energy.

kinetic

The spontaneous mixing of particles of two substances is termed __.

diffusion

With an increase in temperature, the rate of diffusion __.

increases

Particles of matter are held together by a __ of attraction.

force

Among solids, liquids and gases, the force of attraction between particles is maximum in __.

solids

Solids have a definite shape and volume and show negligible __.

compressibility

Liquids take the shape of their container but have a fixed __.

volume

Because they can flow, liquids and gases are collectively called __.

fluids

Gases are highly __, allowing large volumes to be stored in cylinders.

compressible

Random movement of gas particles striking the walls of a container results in __ exerted by the gas.

pressure

The SI unit of temperature is __.

kelvin (K)

To convert Celsius to kelvin, you __ 273 to the Celsius value.

add

Ice, liquid water and water vapour represent the __ states of the same substance.

three

The minimum temperature at which a solid turns into a liquid is called its __ point.

melting

The heat required to change 1 kg of a solid at its melting point into liquid without temperature change is called the latent heat of __.

fusion

Boiling is a __ phenomenon involving the entire bulk of the liquid.

bulk

Changing directly from solid to gas is known as __.

sublimation

Changing directly from gas to solid without becoming liquid is called __.

deposition

Solid CO₂ is commonly called __ because it sublimates at 1 atm pressure.

dry ice

Applying high __ and lowering temperature can liquefy gases.

pressure

Evaporation is a surface phenomenon that occurs at __ temperatures below boiling point.

all/any

Increasing surface area __ the rate of evaporation.

increases

Lower __ (less water vapour in air) speeds up evaporation.

humidity

During evaporation, the liquid absorbs heat from surroundings, causing a sensation of __.

cooling

We wear cotton clothes in summer because cotton absorbs __ and facilitates its evaporation.

sweat

Water in an earthen pot stays cool due to faster __ through the porous walls.

evaporation

At the same temperature, steam contains extra energy equal to the latent heat of __.

vaporisation

Ice at 273 K cools better than water at 273 K because it still needs to absorb latent heat of __.

fusion

The inter-particle spaces are maximum in the __ state.

gaseous

__ is the mass per unit volume of a substance.

Density

The SI unit of pressure is __.

pascal (Pa)

The SI unit of mass is __.

kilogram (kg)

__ heat causes a change of state without a change in temperature.

Latent

In evaporation, particles with __ kinetic energy escape first from the liquid surface.

higher