Some Basic Concepts of Chemistry Class 11 Part 1

Summary

This chemistry class video focuses on the fundamental concepts of chemistry, explaining that it is the study of elements, molecules, and compounds, and their properties and structure. It highlights the importance of chemistry in everyday life, including its applications in medicine, food, and agriculture. The video also discusses the classification of matter into solids, liquids, gases, and further into mixtures and pure substances, including elements and compounds. It emphasizes the balance between the benefits and potential hazards of chemical usage.

Takeaways

• 🔬 Chemistry is the study of elements, their combinations to form molecules and compounds, and the properties, structure, and chemical nature of these molecules.
• 📚 The periodic table is a fundamental tool in chemistry, organizing the 120 known elements.
• 🌐 Chemistry is essential in everyday life as it is involved in the composition of all matter, including living and non-living things.
• 🔑 The concept of matter is central to chemistry, defining anything in the universe that occupies space and has mass.
• 🧬 Biology is intertwined with chemistry, as living organisms are composed of chemicals and undergo chemical reactions.
• 💊 Chemistry plays a crucial role in medicine, with chemicals like cisplatin, taxol, and azido thymidine used in treatments for diseases like cancer and AIDS.
• 🥫 Chemicals are prevalent in food, used as preservatives to extend shelf life and as food colors to enhance appearance.
• 🌱 Agriculture relies on chemicals such as pesticides, insecticides, and fertilizers to protect and nourish crops.
• 🏭 Chemicals are utilized across various industries, including textiles and paint, highlighting their widespread application.
• ♻️ While chemicals are beneficial, overuse of synthetic chemicals can have detrimental effects on the environment, such as ozone depletion and air pollution.
• 🔍 Matter can be classified into solids, liquids, and gases based on physical states, and further into mixtures (homogeneous and heterogeneous) and pure substances (elements and compounds).

Q & A

What is the definition of chemistry as mentioned in the script?

Chemistry is defined as the study of the structure, composition, and properties of matter. It involves not only the study of elements arranged in the periodic table but also the study of molecules, their properties, structure, and chemical nature.

How many elements are there in the periodic table as per the script?

There are 120 elements in the periodic table.

What is the role of chemistry in biology according to the script?

Chemistry plays a crucial role in biology as living organisms' bodies contain chemicals, elements, and compounds, and numerous chemical reactions take place within these bodies.

Why is chemistry important in everyday life?

Chemistry is important in everyday life because chemicals are present in everything we interact with, from the food we eat to the medicines we take. It is involved in various industries and plays a significant role in our daily activities.

What are the two medicines mentioned in the script that are used in cancer therapy?

The two medicines mentioned for cancer therapy are cisplatin and taxol.

What is the chemical used for AIDS patients as per the script?

Azido thymidine, also known as AZT, is the chemical used for AIDS patients.

How is matter classified based on physical state?

Matter is classified into three categories based on physical state: solids, liquids, and gases.

What are the characteristics of a solid as described in the script?

Solids have a definite shape and size, and the atoms or molecules are arranged in a closely packed fashion with strong attractions between them, resulting in a fixed shape and inability to move freely.

How does the script differentiate between a homogeneous and a heterogeneous mixture?

A homogeneous mixture has a uniform composition throughout, like sugar water, whereas a heterogeneous mixture has a non-uniform composition, with components separated in space, such as sand in water where sand settles at the bottom.

What is the difference between an element and a compound as per the script?

An element is a pure substance made up of the same type of particles, like an iron rod made up of iron atoms. A compound is a pure substance made up of different particles, like water, which is made up of hydrogen and oxygen.

Why should the use of artificially synthesized chemicals be limited according to the script?

The use of artificially synthesized chemicals should be limited because they can be more dangerous to the environment and can destroy the well-being of mankind if overused.

Outlines

00:00

🔬 Introduction to Chemistry

This paragraph introduces the subject of chemistry, emphasizing its importance in everyday life. It explains that chemistry is not just the study of elements but also the study of how these elements combine to form molecules and compounds. The periodic table, which arranges these elements, is mentioned as a foundational concept. The paragraph further discusses that chemistry is the study of the structure, composition, and properties of matter, which includes both living and non-living things. It concludes by highlighting the interdisciplinary nature of chemistry, its relevance to other sciences like physics and biology, and its applicability in various fields.

05:00

💊 Chemistry's Role in Medicine and Daily Life

This section delves into the practical applications of chemistry, particularly in the field of medicine. It mentions how chemicals are used to cure diseases, with specific examples including cisplatin, taxol for cancer therapy, and azido thymidine for AIDS patients. The paragraph also touches on the use of chemicals in the food industry, such as preservatives and food colors, and in agriculture through pesticides and fertilizers. However, it warns of the potential negative impacts of chemicals, like the depletion of the ozone layer by chlorofluorocarbons and air pollution from factory emissions, underscoring the need for responsible chemical usage.

10:00

🧪 Classification of Matter

The script explains the classification of matter based on its physical state into solids, liquids, and gases. Solids are characterized by a definite shape and size due to closely packed atoms or molecules with strong intermolecular attractions. Liquids lack a definite shape but have a volume, with particles that can move more freely due to weaker attractions. Gases have neither a definite shape nor size, and their particles are far apart with minimal attraction, allowing for random movement. This classification is fundamental to understanding the nature of matter in chemistry.

15:01

🌐 Mixtures and Pure Substances

This part of the script discusses the classification of matter into mixtures and pure substances. Mixtures are combinations of two or more substances that can be mixed in any ratio, such as sugar in water. Pure substances, on the other hand, consist of a fixed ratio of elements, like water (H2O). The paragraph further differentiates mixtures into homogeneous (uniform composition throughout, like saltwater) and heterogeneous (non-uniform composition, like sand in water) mixtures. Pure substances are classified into elements, which are made up of the same type of particles, and compounds, which consist of different particles combined in a fixed ratio.

20:02

📚 Recap and Preview of Upcoming Topics

The final paragraph summarizes the classification of matter based on physical state and general composition. It recaps the distinctions between solids, liquids, gases, mixtures (homogeneous and heterogeneous), elements, and compounds. The speaker then teases the next video, which will focus on the properties of matter, encouraging viewers to subscribe for more easy-to-understand lessons on chemistry.

Keywords

💡Chemistry

Chemistry is defined in the script as the study of elements, molecules, and compounds. It is crucial for understanding the composition, structure, and properties of matter. The video emphasizes that chemistry is not just about the periodic table but also how atoms combine to form molecules and the properties of these molecules. It is integral to everyday life, from the air we breathe to the food we eat.

💡Elements

Elements are the basic building blocks of matter, consisting of a single type of atom. The script mentions there are about 120 elements found in nature, which are arranged in the periodic table. Elements combine in specific ways to form molecules and compounds, highlighting their importance in chemistry.

💡Molecules

Molecules are groups of atoms bonded together, representing a fundamental concept in chemistry. The script uses the example of oxygen molecules, which are formed by the combination of two oxygen atoms. Molecules are central to understanding chemical reactions and the properties of substances.

💡Compounds

Compounds are substances formed when two or more elements combine in a fixed ratio. The script gives the example of water (H2O), which is a compound formed from hydrogen and oxygen. Understanding compounds is essential for grasping chemical composition and reactivity.

💡Matter

Matter is defined in the script as anything that occupies space and has mass, including both living and non-living entities. It encompasses all the substances studied in chemistry, whether they are elements, molecules, or compounds.

💡Physical State

Physical state refers to the form in which matter exists, such as solids, liquids, and gases. The script explains that these states are determined by the arrangement and movement of atoms or molecules within the matter, affecting its properties like shape and volume.

💡Solids

Solids are a state of matter with a definite shape and volume. The script mentions that in solids, atoms or molecules are closely packed with strong intermolecular attractions, which prevent them from moving freely and maintain the solid's shape.

💡Liquids

Liquids do not have a definite shape but maintain a definite volume. As explained in the script, the molecules in liquids have weaker intermolecular forces, allowing them to move more freely but still be confined within a container's boundaries.

💡Gases

Gases are matter without a definite shape or volume. The script illustrates that gas molecules have significant spaces between them and weak intermolecular forces, leading to free and random movement, which can expand to fill any container.

💡Mixture

A mixture, as described in the script, is a combination of two or more substances that are not chemically bonded and can be present in any ratio. Examples include saltwater or sugar dissolved in water. Mixtures can be either homogeneous, where the components are uniformly distributed, or heterogeneous, where the components are not uniformly distributed.

💡Pure Substance

A pure substance, as explained in the script, has a consistent composition throughout and can be either an element or a compound. Pure substances are uniform at the molecular level, unlike mixtures, and include substances like water (H2O), which despite being composed of hydrogen and oxygen, is considered a pure substance because the elements are combined in a fixed ratio.

💡Element

Elements are pure substances consisting of only one type of atom. The script uses iron as an example of an element, which is made up entirely of iron atoms. Elements are the simplest form of matter and are the basis for all chemical compounds.

💡Compound

Compounds are pure substances composed of two or more different elements chemically combined in a fixed ratio. The script explains that water is a compound made of hydrogen and oxygen in a 2:1 ratio. Compounds are distinct from the elements they are made from, having unique properties.

Highlights

Introduction to the basics of chemistry and its importance in everyday life.

Chemistry defined as the study of elements, molecules, and their properties.

Explanation of how elements combine to form molecules and compounds.

Chemistry's role in studying the infinite variety of molecules in nature.

Matter defined as anything in the universe that occupies space and has mass.

Chemistry redefined as the study of the structure, composition, and properties of matter.

Interconnection of chemistry with other branches of science like physics and biology.

Importance of chemistry in medicine, particularly in cancer therapy and AIDS treatment.

Chemicals' widespread use in food, agriculture, and various industries.

The potential dangers of chemical use, such as ozone layer depletion and air pollution.

The need for responsible use of chemicals to avoid environmental harm.

Classification of matter into solids, liquids, and gases based on physical state.

Characteristics of solids, including definite shape and closely packed atoms.

Explanation of liquids' lack of definite shape but presence of volume.

Gases defined as having no definite shape or size and free movement of particles.

Matter can also be classified as mixtures or pure substances.

Mixtures are combinations of two or more substances without a fixed ratio.

Pure substances have a fixed ratio of elements, like water (H2O).

Mixtures can be homogeneous, where composition is uniform, or heterogeneous.

Pure substances are further divided into elements and compounds.

Elements are pure substances made of the same type of particles, like an iron rod.

Compounds are pure substances made of different particles, like water (H2O).

Transcripts

[Music]

hey everyone

welcome to homeschool and welcome to

class 11 series

chemistry uh see we have already done a

video on

class 11 chapters overview where i

explained about what are the chapters

that is there in class 11 chemistry

and a brief introduction about them

isn't it and

this is the video on the very first

chapter that is basic concepts

of chemistry so here first of all let us

deal with what is actually the chemistry

is and what is the importance of

chemistry in everyday life

clear so if i ask you to define the

chemistry

how do you define a chemistry see many

of them who tell chemistry

is the study of elements right and we

have so-called

elements in our nature right now 120

elements and they are beautifully

arranged

in the form of a table called periodic

table

we all know the basics of periodic table

that we have learnt in class 10

isn't it see according to that people

who think that

it is the study of those elements not

only the study of

those elements and you know these

elements what do they do

the elements would combine with each

other to

form molecules and compounds isn't it

say for example you have one oxygen atom

would combine with

another oxygen atom you would get oxygen

molecule

or you have hydrogen molecule itself

that would combine with oxygen molecule

and you may get

a new compound called h2o right

see these are the elements they are

combining to give molecules

so chemistry is not only the study of

these elements that is very nicely

arranged in a periodic table

it is also the study of these molecules

it is the study that involves how these

atoms or elements have combined

to give molecules and it is the study of

those molecules their properties their

structure

their chemical nature and everything

right

say chemistry is the study of infinite

molecules

and you don't have limited number of

molecules in our nature you have

infinite endless countless number of

molecules

so it is the study of all those

molecules

nature structure composition and what

not

it is everything right and where are

these

molecules or compounds or elements

present

they are present in the matter itself

right so what do you mean by

matter this is not a new word for you

say matter is anything in the universe

uh that occupies space isn't it

occupies space and has

some mass such a thing is called

matter are we matter definitely we are

matters

and this chalk piece is a matter air is

a matter

everything is a matter because if you

take this chalk piece it has certain

mass

and it is occupying some space in this

universe

so i can call this chalk piece as a

matter like that if you see

all living things that you see from your

eye and non-living things that you see

from your

eye everything is a matter right

so i will redefine chemistry now here

i can define chemistry as it is the

study of

study of structure composition

and properties

of matter here so this becomes a perfect

definition for chemistry it's not only

the study of

elements it is the study of that

infinite countless number of molecules

and where are these countless number of

molecules and these elements present

definitely in so-called matter so they

are present in

everything that we see from your from

our eyes isn't it

so ultimately i can say study of

structure

composition and properties of matter

is called chemistry isn't it

say and now can you able to tell me

what is the importance of chemistry why

do we need to study

this branch of science and this

branch of science is dependent on

other branches of size you know all the

branches of signs are

interconnected with each other what are

the different branches of science

physics is a branch biology is a branch

chemistry is a branch

right so these are all various branches

of science and they are all

interdependent one branch is dependent

on another

right and you know what what do you mean

by biology

biology is a study of life biology is a

study of human body

organisms body plants body and what does

the body contain

any living organisms body contain

the chemicals the so it's a matter right

so it contains lots of elements lots of

compounds and too many chemical

reactions

are taking place inside the body right

say here also chemistry is

involved so there is no biology without

any chemistry

and there is no chemistry without any

biology right

so similarly even our physics is

dependent on chemistry chemistry is

dependent on physics so

all these branches are interconnected

interdependent with each other

okay so now what is the importance of

studying chemistry in everyday life

phase

we see chemicals everywhere right we eat

chemicals the food we eat

is a chemical only right and the water

we drink is a chemical only like that if

we see

morning soon after we get up until we go

to the bed

we are connected with so-called

chemicals

all around they may be natural they may

be artificial chemicals right

but definitely we depend on chemicals

right and let us see some examples

chemicals

are widely used in the field of

medicine right see nowadays

every disease can be cured with the help

of

medicine and this medicine is nothing

but chemicals

they these chemicals are prepared by

various other

reactions i can say and you know two

such chemicals i will

mention here they are very very

important there is a chemical called

cis plating these are the things

mentioned in your ncip books

so i'm mentioning here cis platinum and

another uh medicine called taxol

so these are the two medicines which are

used

in cancer therapy so

to cure a cancer we use certain

chemicals they give treatment with the

help of chemicals called chemotherapy

so in chemotherapy cisplatin and taxol

are the chemicals which are

used right and also

there is another chemical called

acetothymidine

azido thymidine and this is the chemical

which is used uh for aids patients

used for aids patients say

uh likewise if we go on mentioning the

chemicals you know the parasite

we take when we get a fever analogistics

that we take as pain killers you know

all these are various chemicals only

right

so chemicals play a lot of importance in

the field of

medicine and now i can say chemicals in

food

chemicals in food even in the food

industry

the preservatives that we use

preservatives that means uh

using this we can store food for a

longer time

uh they are called as preservatives and

we can use food colors

right so various other things we use in

the food industry also

and the chemicals in agriculture say

agriculture uh nowadays

too many different types of farmings are

available

natural or artificial chemical usage

farming

whatever it is the chemicals are widely

used

so chemicals are used in the form of

pesticides right insecticides

and what not you can use them as

fertilizers

right so in a different way it can be

used even in the agriculture

right like that if we go on mentioning

there are various industries textile

industry paint industry

uh you know every industry uh chemicals

are used

and now we have lots of uses with

different types of chemicals at the same

time

we have so many side effects of using

chemicals also

say for example chlorofluorocarbons that

we use in the refrigerators

cause you know ozone layer depletion

isn't it and likewise the gases like

sulphur dioxide nitrogen dioxide

uh these are the gases that come out

from the factories

even they cause the air pollution you

know they are responsible for

acid rain likewise if we go on telling

the dangerous aspects of chemicals

numerous numerous things are there say

one point i would like to tell you is

yes we use chemicals for the benefit of

man at the same time

we have to limit the usage of

artificially synthesized chemicals

because they are more dangerous to the

environment

so we have to use them in a

limited way otherwise it would destroy

uh the well-being of mankind right so

chemicals has

both benefits as well as uh hazardous

things also

so this point we have to keep it in a

mind and then

a proper usage of chemicals may give

enough benefit to a man but when you

overuse it

it could destroy the well-being of man

isn't it so this is some introduction

about

uh the chemistry and the importance of

chemicals and dangerous aspects of

chemicals

and now without wasting much time let me

move on to the next

concept that is nature of matter

because chemistry is all about

the study of matter isn't it so let us

see what are the different

types of matter i mean matter can

again be classified into so many types

and let us see what are those types and

what is their

nature see guys based on the physical

state

matter can be classified into three

categories

one is solids liquids

and gases isn't it this way of

classification we have

learned it in our earlier classes also

so this classification

is mainly based on

physical state of matter physical

state clear okay so now what do you mean

by solid say this chalk piece is a solid

board is a solid

say solids are a type of a matter

which have definite shape and size

so they have definite shape and

size isn't it and you know uh

in a solid the atoms are arranged

in a closely packed fashion i mean

between

one atom and another atom or these guys

may be

molecules see matter is made up of

atoms or molecules so it may be

an atom or it may be a molecule of

matter

between the molecules or atoms

you have lots of attraction between them

okay so that is the property of solids

clear

that is the reason they have a proper

shape

and a proper size okay

and coming to the liquids and liquids

do not have a definite shape

no definite shape

but they have volume

they have so called volume okay

and in a liquid uh whatever the atoms

are molecules

present in the liquid matter they can

move

they have a ability of moving it's

because

you know the atoms or a molecules

would have a space between them that's

the reason

there is no much attractions between the

atoms and

molecules of liquids that's the reason

they can

freely move whereas in the solid there

is no movement of atoms and molecules

okay fine and what do you mean by a

gases

say oxygen gas hydrogen gas which are

present in the atmosphere

uh what do they have they do not have

any

shape and no shape no

size also clear and

you know if you see the atoms or

molecules in a gas

you can see lots of spaces are there in

between

and there are no much attractions

between the atoms or molecules

so they can very nicely move in a

random way isn't it and you can see the

atoms and molecules of solid how i have

shown you it

is there's no gap between them and they

are closely packed

uh that's the reason they have a

particular shape and they can't move

and here these guys have little

attractions

and uh you know they have little spaces

between

each other and they are free to move and

here

uh the freedom of movement is too much

they can move very nicely in a random

way

say this is some basic aspects about

solids liquids and gases clear fine

and now the matter can also be

classified

uh into you know mixture and

pure substance clear there is another

classification of

matter that we have already studied in

our previous classes

it been can be classified

as mixture and pure substance

and now let us discuss what do you mean

by

a mixture and mixture is nothing but

a combination of combination

of two or more

substances substances is nothing but any

kind of a matter

if two or three types of matter is

mixed together then we call it as

mixture

okay and you know they have been

combined

in any ratio in any ratio

okay they they there is no fixed ratio

for the mixture say for example if i say

sugar

in water sugar in

water when i put a spoon of sugar in

water it becomes a mixture

sugar is one type of matter water is

another type of matter

this is one substance this is another

substance and

i'm combining both of them so i can call

this as a mixture now

okay and you can mix these things in any

ratio

right so you can add one spoon of sugar

in one liter of water or you can

add once one spoon of water

in so much amount of sugar you know

there's no perfect ratio like this much

amount of sugar has to be combined in

this much amount of water

right so you can mix these things in any

proportion in

any ratio then you will normally call it

as

mixture okay and now what do you mean by

a pure substance

you know pure substance is a pure

chemical substance

where two substances i mean two

different

patterns can be combined but with a

fixed ratio

so here you have a fixed ratio

okay say for example water water

is called as a pure substance okay you

you can ask me like it's a combination

of hydrogen

and oxygen no ma'am how you will call it

as a pure substance

i have to call this as a mixture no you

know this is a doubt you will get

but you see how is water formed water

has

formed by the combination of two atoms

of

oxygen with one atom of oxygen isn't it

so only then water is formed when two

hydrogen atoms would combine with one

oxygen atom

only then water is formed that means

they are combining in a fixed ratio they

are not combining

in how many how much ever they want

however

they want isn't it say when the two

different

matters they this is one element this is

an

another element both are matters only

but combining in a fixed ratio

so water is called as a pure substance

and sodium metal is called as a pure

substance oxygen

gas is a pure substance right a single

element or

it may be a molecule or compound but if

it is combined in a fixed

ratio then we can call it as a pure

substance

clear fine and now coming to the mixture

mixture is again classified into two

types

one is homogeneous mixture

and other one is heterogeneous mixture

right okay so what do you mean by

homogeneous mixture

here the composition is uniform

throughout

composition is uniform

what do you mean by composition is

uniform here

say okay let me give one example first

sugar water sugar water or

salt water is the example and let me

give an example here heterogeneous

heterogeneous in the sense

composition composition

is not uniform

observe the example sand

sand plus water imagine if you

put a one spoon of sand in a beaker of

water

will you have sand particles throughout

the water

no right all the sand would go at the

bottom and they would settle

i mean sand is there only at the bottom

of the water

what about the top surface of water it

is pure it's only a water

there will not be any sand that means in

entire water

the sand particles are not present right

they they are restricted to one

particular

area in water medium isn't it so that's

what we mean by heterogeneous

that's what we mean by composition is

not uniform

that means sand particles are not

present

all through the water right they are

restricted to one particular place they

went

to the bottom and they got settled isn't

it but

if you put one spoon of sugar in water

and nicely when you mix it

what happens you will have sugar

particles throughout the water

at the bottom of the water you have

sugar plus water

on the surface of the water also you

have sugar particles

in the middle of the beaker also you

have sugar particles isn't it

so sugar particles are spread evenly

uniformly throughout the water right

that such a mixture we will call it as

homogeneous

here everyone that's all and now pure

substance is again classified

into element and

compound okay now

what do you mean by element element

are those substances which are

made up of with same particles

they are made up of with same particles

so what do you mean by the element is

the pure substance made up of same

particles

if you take up iron rod okay say

at every corner of this particular iron

rod

you have the same particles called iron

atoms

so this iron rod would have cross of

iron atoms but

all are iodine atoms only you don't find

any other atom in between

right say such a substance

such a pure substance which is made up

of

same particles here the particle is atom

isn't it so matter is made up of atoms

and molecules

matter is made up of molecules molecules

is again

formed by the combination of atoms so

ultimately

what is the smallest particle of matter

atoms

so if a pure substance is made up of

same type of particles

then we call it as element so what do

you mean by compound

compound means made up of different

particles

compound is a pure substance made up of

different particles say for example

water here

okay so water is pure one but it is made

up of

two different elements that is hydrogen

and oxygen

isn't it so this is some basic

introduction about

how matter is classified based on the

physical state we can classify this

into solids liquids and gases and based

on the general way i can classify matter

into mixture impure substance

mixture is again into homogeneous

mixture and heterogeneous mixture

pure substance is again into element and

compound

so this is all about nature of

matter so in my next video we will

discuss about

the properties of mata okay meet up in

the next

session till then take care and do

subscribe our channel to learn the

concepts in the easiest way

thank you so much