Matter In Our Surroundings

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Introduction

• Everything in this universe is made up of material that scientists have named “matter”.
• Anything that has mass and occupies space is called matter.
• For example:- Chair, Sugar, Sand, Air, Honey, Oil, Perfume, Clouds, Stars, Planets, etc.
• Early Indian philosophers classified matter in the form of five basic elements – the “Pancha Tatva”– air, earth, fire, sky, and water. According to them everything, living or nonliving, was made up of these five basic elements.

• Modern-day scientists have evolved two types of classification of matter based on their physical properties and chemical properties.

Properties of Matter

The properties of matter are the characteristics that help us identify and differentiate one substance from another. These properties are broadly classified into physical properties and chemical properties.

1. Physical Properties

Physical properties are those properties of a substance that can be observed or measured without changing the chemical composition of the substance. In other words, the substance remains the same even after observing these properties.

Examples of physical properties include:

• Density
• Colour
• Taste
• Hardness
• Melting point (M.P.)
• Boiling point (B.P.), etc.

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2. Chemical Properties

Chemical properties are the properties that describe how a substance reacts to form a new substance. Observing these properties involves a chemical change, and the original substance does not remain the same.

Examples of chemical properties include:

• Acidic or basic nature
• Reactivity with other substances
• Combustibility, rusting, etc.

• What matter is made up of?

For a long time, two schools of thought prevailed regarding the nature of matter. One school believed matter to be continuous like a block of wood, whereas, the other thought that matter was made up of particles like sand. However, it was later proved that matter is made up of particles.

Matter consists of small particles called atoms and molecules which act as a building block.

Characteristics Of Particles Of Matter

1. Particles of matter are very, very small in size
2. Particles of matter have space between them
3. Particles of matter are in continuous motion
4. Particles of matter attract each other

• Note: All these characteristics of particles are followed by all particles of any matter.

• Particle Nature: Matter is made up of tiny, discrete particles. These particles can be atoms, molecules, or ions, depending on the substance.

• How small are particles of matter?

The particles of matter are very small in size. They are so small that they cannot be seen even with microscope.

STM (Scanning Tunneling Microscope) can take image of atom.

The particles of matter are very small in size– they are small beyond our imagination!!!!

STM (Scanning Tunneling Microscope)

• Particles of matter have space between them

1. Interparticle Space: There is empty space between particles in matter. The amount of empty space depends on the state of matter.
2. For example, in gases, particles are widely separated, while in solids, particles are closely packed.
3. Particles of sugar, salt, Dettol, or potassium permanganate get evenly distributed in the water. This shows that there is enough space between particles of matter.

• Particles of matter are in continuous motion

1. Particles of matter are continuously moving, that is, they possess kinetic energy since particles start vibrating from their mean position. As the temperature rises, particles move faster. So, with an increase in temperature, the kinetic energy of the particles also increases.
2. Diffusion – This intermixing of particles of two different types of matter on their own is called diffusion. As the temperature increases, diffusion becomes faster.

Diffusion

• Rate of diffusion is fastest in gases and slowest in solids.
• Rate of diffusion increases on increasing temperature because on increasing the temperature of a diffusing substance, its particles gain kinetic energy and move more rapidly.

• Rate of Diffusion: Solids < Liquids < Gases

• Particles of matter attract each other

1. Forces Between Particles: There are attractive forces between particles in matter.
2. Particles of matter attract each other because of the interatomic attraction force present between them. This force keeps the particles together. The strength of this force of attraction varies from one kind of matter to another.

Some Other Characteristics Of Particles

• Arrangement of Particles: The arrangement of particles in different states of matter varies. In solids, particles are tightly packed in a regular and ordered manner. In liquids, particles are still close together but more randomly arranged. In gases, particles are widely spaced and have a random arrangement.
• Compressibility: Particles in solids are generally not very compressible because they are closely packed. In contrast, particles in gases are highly compressible because they are far apart and can be pushed closer together under pressure.
• Expansion: When the matter is heated, the particles gain kinetic energy and move apart, causing the substance to expand. Conversely, when matter is cooled, the particles lose kinetic energy and move closer together, leading to contraction.
• Melting and Boiling Points: Each substance has specific temperatures at which it changes from one state of matter to another.

States Of Matter

• Based on physical properties, matter can be classified into three categories:

• In addition, the other types of matter found in some other special conditions are as follows.

1. Plasma state
2. Bose-Einstein Condensate

Characteristics	Solids	Liquids	Gases
Mass	Definite (Fixed)	Definite	Definite
Shape	Definite	Indefinite	Indefinite
Volume	Definite	Definite	Indefinite
Density	Maximum	Intermediate	Maximum
Arrangement Of Particles	Compact	Nearby	Faraway
Rate Of Diffusion	Slow	Intermediate	Fast
Force Of Attraction	Maximum	Intermediate	Minimum
Compressibility	Not compressible	Intermediate	Highly Compressible

• Plasma

1. Plasma is considered the fourth state of matter.
2. Plasma state consists of super energetic and super excited particles.
3. These particles are in the form of ionized gases.
4. Example – The sun and the stars glow because of the presence of plasma in them.
5. Application- Practical applications include fluorescent lights, plasma TVs, plasma cutting, semiconductor manufacturing, and nuclear fusion for clean energy.
6. Occurrence:

Plasmas occur naturally in stars, lightning, and flames, and are also created for research in laboratories.

Bose – Einstein Condensate

1. In 1920, Indian Physicist Satyendra Nath Bose had done some calculations for a fifth state of matter. Based on his calculation, Albert Einstein predicted a new state of matter.
2. Bose-Einstein condensate is obtained by cooling a gas of extremely low density to super low temperature.
3. BECs are formed at temperatures close to absolute zero
4. Example – Liquid Helium

Change In State Of Matter

• A change in the state of matter refers to the transformation of a substance from one physical state to another.
• Changing states of matter occurs when matter loses or absorbs energy.
• Physical state of matter can be changed in two ways:                                        

1. By changing the temperature
2. By changing the pressure

1. Melting- The process by which a substance changes from a solid state to a liquid state when heated is called melting.
2. Freezing- The process by which a substance in a liquid state changes into a solid state when cooled is called freezing.
3. Evaporation- The process by which a substance changes from a liquid state to a vapor state when heated is called evaporation.
4. Condensation- The process by which a substance in the gaseous state changes into its liquid state when cooled is called condensation.
5. Sublimation- Sublimation is the process by which certain substances change directly from a solid to a gaseous state when heated.
6. Deposition-  Deposition is the process by which certain substances change directly from a gaseous state to a solid state when cooled.

Examples Of Phase Transition In Matter

1. Melting: Ice (solid water) melts into liquid water when heated.
2. Freezing: Liquid water freezes into ice when cooled.
3. Vaporization/Evaporation: Boiling water produces steam (water vapour). Puddles dry up as water evaporates.
4. Condensation: Water droplets form on a cold glass on a hot day.
5. Sublimation: Dry ice (solid carbon dioxide) turns directly into carbon dioxide gas when exposed to room temperature.
6. Deposition: Frost forms on a cold surface as water vapor changes directly into ice crystals.

Important Terms Related To Temperature

• Melting point – The melting point is the specific temperature at which a solid substance changes into a liquid when heated at a constant pressure. The vapour pressure of solid and liquid becomes equal at this temperature.
• Boiling point – The boiling point is the specific temperature at which a liquid substance changes into a gas when heated at a constant pressure. The vapour pressure of the liquid becomes equal to atmospheric pressure at this temperature.
• Freezing points – The freezing point is the specific temperature at which a liquid substance changes into a solid when cooled at a constant pressure. It is the reverse of the melting point.

Effect Of Change Of  Temperature

1. Latent heat –  The hidden heat which breaks the force of attraction between the molecules during a change of state.
2. Latent heat of fusion – The amount of heat energy that is required to change 1 mole of a solid into liquid at atmospheric pressure without any changes of temperature at its melting point is known as latent heat of fusion.
3. Latent heat of vaporization– It is defined as heat required to convert 1 mole of liquid into vapours completely at this boiling point.

• Note: The particles of vapor, e.g.,steam have more energy than particles of liquid e.g.,water at the same temperature because particles of vapors,i.e.,stem have absorbed extra energy in the form of latent heat of vaporization.

Effect Of Change Of  Pressure

• Effect of change of pressure – 
• If pressure is applied to a substance its state changes from:

Gas →Liquid → Solid.

• When we increase the pressure also, then intermolecular force of attraction increase to large extent and CO₂ gas can be converted into solid.
• Solid CO₂ gets directly converted to gaseous state on decreasing the pressure to 1 atmosphere without becoming liquid, that is why it is called dry ice.

Difference Between Evaporation & Boiling

EVAPORATION	BOILING
Evaporation is surface phenomenon	Boiling is bulk phenomenon
Evaporation is a gradual process	Boiling is vigorous process, with the formation of bubbles throughout the liquid.
During evaporation, liquid temperature drop	During boiling, liquid temperature remain unchanged

Evaporation

• The phenomenon of change of a liquid into vapor at any temperature below boiling point is called Evaporation.

• Why evaporation takes place ?

It occurs at all temperatures as the molecules on the surface keeps escaping out of the surface by gaining energy from the environment.

Factors Affecting Evaportaion

1. Temperature

With increase in temperature, more number of particles get enough kinetic energy to go in vapor state.

Temperature ∝ Evaporation

2. Surface Area

It is because, if larger surface area is exposed to air, more molecules will escape into the air.

Surface Area ∝ Evaporation

3. Humidity: It represents the amount of water vapor present in it.

If Humidity is less, then air is more dry and hence rate of evaporation is fast.

Humidity ∝ 1/Evaporation

4. Wind speed:

Wind Speed ∝ Evaporation

Because with increase in wind speed the particles will move away.

Evaporation Causes Cooling Effect

The cooling caused by evaporation is based on the fact that when a liquid evaporates, takes latent heat of vaporization from the surrounding which on losing heat gets cool.

Basic Concepts On Temperature

• Units of Temperature:

1. ⁰C
2. ⁰F
3. K

• The SI unit of temperature is– Kelvin (K)
• The formula to convert temperatures in Celsius to Kelvin is
  K = 273.15 + ⁰C
• This formula is sometimes approximated simply as –
  K = 273 + ⁰C

Fahrenheit Temperature

• The Fahrenheit temperature (°F) scale is named for German physicist Daniel Gabriel Fahrenheit and is the measurement of temperature. On the Fahrenheit scale, water freezes at 32°Fand boils at 212°F(at sea level).
• The Celsius temperature (°C)scale – originally called centigrade and later renamed for Swedish astronomer Anders Celsius, is used almost everywhere else in the world. On the Celsius scale, water freezes at 0°Cand boils at 100°C(at sea level).
• The formula to convert temperatures in degrees Fahrenheit to Celsius is –
  °C = 5/9 × (°F-32)