Introduction
Definition
Chemistry is the study of composition, properties, and reactions of matter, particularly at the
level of atoms and molecules, how and why substances combine or separate to form other
substances, and how substances interact with energy.
Importance of Chemistry in life
Chemistry is important because everything you do is chemistry! Even your body is made of
chemicals. Chemical reactions occur when you breathe, eat, or just sit there reading. All matter
is made of chemicals, so the importance of chemistry is that it's the study of everything.
Chemical reactions takes place in plants and animals, this result in the formation of substances
in some plants and animals that can be used to treat illness. Chemistry is important to everyday
life, because it provides medicine. The food we consume each day comes directly
from chemical processes.
Everything on earth is made up of chemicals: you, your food, and the products you use in daily
life such as soaps, perfumes etc. all are made up of chemicals. Life without chemicals is
impossible. A number of changes that you observe are the result of chemical reactions like the rain, the
change in the color of leaves, cleaning of any particular material in your house, all involve chemicals.
Chemistry is important because it helps in exploring things which are unknown to mankind.
Chemistry is important because it explains the future behavior of plants and animals and all of
us use chemicals directly or indirectly in our daily lives.
We are using chemistry when we cook, when we wash, when we eat, when we get ready, when
we play, when we think, as a matter of fact, we always use chemistry. Increasing our knowledge
in chemistry is essential if we want to improve our daily lifestyle.
Chemistry is also important for the environment. When you are aware of the harmful effects of
the gases like carbon dioxide and methane as a result of the greenhouse effect, you can easily
carve out the solutions for the reduction of its effects on the environment. If you possess a
minimum knowledge of the importance and use of chemistry you can help in saving the
environment to a large extent.
Branches of Chemistry
Following are the some important branches of Chemistry.
Organic Chemistry
 It is the study of the structures, properties and behavior including reactions of
compounds containing C-H bonds.
 Branch of Chemistry which deals with the study of organic compounds and substances
produced by living organisms.
 The study of carbon and its compounds; the study of the chemistry of life.
Inorganic Chemistry is the study of compounds not-covered by organic chemistry; the study of
inorganic compounds or compounds which do not contain a C-H bond. Many inorganic
compounds are those which contain metals.
 Inorganic chemistry is the study of the properties and behavior of inorganic compounds.
It covers all chemical compounds except organic compounds.
 Inorganic chemists study things such as crystal structures, minerals, metals, catalysts,
and most elements in the Periodic Table.
Physical Chemistry deals with the explanation of fundamental laws and principles.
 Physical chemistry is the study of how matter behaves on a molecular and atomic level
and how chemical reactions occur. Based on their analyses, physical chemists may
develop new theories, such as how complex structures are formed.
 Examples are electrochemistry, thermochemistry, photochemistry, spectroscopy,
chemical kinetics.
Analytical Chemistry deals with the qualitative and quantitative analysis of chemical
substances.
Matter
Anything which occupies space and has some mass is called matter. It is made up of small
particles which have some space between them. The matter particles attract each other and
are in state of continuous motion.
Figure on board
Elements are chemically the simplest substances and hence cannot be broken down
using chemical reactions. It contains only one kind of atom.
 Hydrogen is the most abundant element in the earth crust.
 Oxygen (non metal)
 Aluminium ( metal)
Compound
It is also the form of matter which can be formed by combining two or more elements in a
definite ratio. It can be decomposed into its constituent elements by suitable chemical
reactions.
Compounds can be of two types
 Inorganic compounds
It was believed that these compounds are derived from non living sources like rock and
minerals. But these are in fact the compounds of all the elements except hydrides of carbon
(hydrocarbon) and their derivatives.
 Organic compounds
According to earlier scientists, these compounds are derived from living sources like plants and
animals, or these remain buried under the earth i.e. petroleum. Organic compounds are
hydrides of carbon and their derivatives.
Mixture
In chemistry, a mixture is a material made up of two or more different substances which are
mixed but are not combined chemically. A mixture refers to the physical combination of two or
more substances in which the identities are retained and are mixed in the form of solutions,
suspensions, and colloids.
A mixture is the blending of two or more dissimilar substances. A major characteristic of
mixtures is that the materials do not chemically combine.
Types of mixtures
There are two types of mixtures.
1) Homogeneous mixtures
2) Heterogeneous mixtures
A homogeneous mixture is a solid, liquid or gaseous mixture that has the same proportions of
its components throughout a given sample (or multiple samples of different proportion).
Conversely, a heterogeneous mixture is not uniform in composition, but proportions of its
components vary throughout the sample.
Examples of Homogeneous Mixtures
Here are some examples of homogeneous mixtures:
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Water itself is an example of a homogeneous mixture. It often contains dissolved minerals and
gases, but these are dissolved throughout the water. Tap water and rain water are both
homogeneous, even though they may have different levels of dissolved minerals and gases.
A bottle of alcohol is a man-made homogeneous mixture.
In the human body, blood plasma is an example of a homogeneous mixture. This is a colorless
fluid that holds the blood cells in suspension.
A cup of coffee is considered a homogeneous mixture. Does that change when sugar is
dissolved into it? As a matter of fact, if the sugar is completely dissolved, the coffee is still
considered homogeneous, since the mixture of coffee and sugar is uniform throughout the cup.
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Mouthwash is a homogeneous mixture example. Mouthwashes typically contain a percentage
of alcohol along with a variety of different chemicals aimed at keeping the teeth and gums
clean and the breath fresh.
Detergent is another example of a homogeneous mixture of various soaps and chemicals that
keep clothes clean.
A bottle of vinegar is a man made homogeneous mixture.
The air that you breathe is a homogeneous mixture of oxygen, nitrogen, argon, and carbon
dioxide, along with other elements in smaller amounts. Because each layer of the
Earth’s atmosphere has a different density, each layer of air is its own homogeneous mixture.
That perfume is a perfectly homogeneous mixture of chemicals and dyes.
Gunpowder, which is used in a variety of explosives, is actually a homogeneous mixture of
elements like sulfur, charcoal, and saltpeter (also known as potassium nitrate).
Many beverages are examples of homogeneous mixtures, orange juice, glass of water and the
cup of tea.
Put some soap into a glass of warm water, cover it, and shake it up – the mixture of soapy
water will in fact be homogeneous in composition.
An alloy is a metal comprised of two pure metals. Alloys such as steel and bronze are
homogeneous mixtures of two metals.
The bottle of vegetable oil so often used in cooking is a homogeneous mixture.
Examples of Heterogeneous Mixtures
Here are some examples of very common heterogeneous mixtures:
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A bowl of Fruit is a heterogeneous.
Sand shaken up in a bottle of water is a heterogeneous mixture of sand particles floating
around which will eventually settle to the bottom of the bottle, making it look a lot less like a
mixture.
Rocks in the sand at the beach are a heterogeneous mixture – all different shapes, sizes and
colors.
Smog is a heterogeneous mixture of various particles suspended in the air. The dirty particles
that make up the smog can be removed from the air and breathed into the lungs, making smog
quite a problematic heterogeneous mixture.
Mixed nuts are a type of heterogeneous mixture that can be separated simply by pouring them
onto a table and sorting them.
Pizza is a heterogeneous mixture of dough, sauce, cheese, and other toppings.
Soil is an example of a heterogeneous mixture that combines many different elements which
are not uniform.
Sand is a heterogeneous mixture of rock, shells, metals, and other elements.
Mixture examples
Simple mixtures can involve various combinations of solids, liquids and gases.
Solid in solid
Sand is an example of a suspension mixture of solid particles. By sifting the sand, you can
separate particles according to size.
Solid in liquid
Muddy water is an example of solid particles mixed in a liquid. Dirt is added to the water and
made into a mixture by stirring the ingredients. After a while, gravity will cause the particles to
settle to the bottom.
Blood is another example of solid particles in a liquid. The blood cells can be separated with a
centrifuge.
Solid in gas
Smoke is an example of solid particles mixed in a gas.
Liquid in liquid
If you thoroughly mix the solute oil and the solvent water, the mixture will soon separate. Oil
and water do not mix on a permanent basis.
Liquid in gas
Liquid particles can mix in a gas but will soon separate out. An example is a fine mist spray of
water particles in air.
Gas in liquid
Bubbles of air or a gas can be seen in a liquid. Being lighter, they soon rise to the top.
Gas in gas
Gases mix at a molecule level. Air is a homogeneous mixture of Oxygen molecules, Nitrogen,
Carbon Dioxide and some other gases.