Matter is everything around you. Matter is anything made of atoms and molecules. Matter is anything that has a mass. Matter is also related to light and electromagnetic radiation. Even though matter can be found all over the universe, you usually find it in just a few forms. As of 1995, scientists have identified five states of matter. They may discover one more
Matter has
mass and
occupies space. All matter is composed of basic elements that cannot be broken down
to substances with different chemical or physical properties.
Matter is classified into two major categories:
Pure Sustances &
Impure Substances(Mixtures).
Pure Substances is further classified into
Elements &
Compound. Impure Substances is further classified into
Homogeneous &
Heterogeneous Mixtures.
Properties Of Matter
There are
four different properties of matter. They are mass, volume, density and weight,.
Mass
The most important one is
Mass. Mass is the
amount of matter in an
object and it never changes unless matter is taken out of the object.
Mass also has a direct relationship with inertia.
Inertia is the resistance of motion of an object. If an object has a greater mass, then it has a greater inertia.
Volume
Volume is another general property of matter. Anything that takes up
space has volume.
In fact, volume is the
amount of space an object takes up. You can find a straight-edged
object's volume by measuring the Length x Width x Height. For irregular shaped objects,
you'd probably want to use a graduated cylinder.
Litres and millilitres are used to measure
the volume of liquids, while
cubic centimeters are used to measure solids.
Density
The third general property of matter is
Density. Density is very important because
it enables you to
compare different objects. For instance,
water has a density of
1 gram/cc and
wood is
0.8 grams/cc. Therefore, wood will float in water because
it's density is less than that of water. The equation for density is
Density=Mass/Volume.
Also, if you split an object in half, it will still have the exact same density.
Weight
Weight is the fourth general property of matter.
It is defined as the
measure of force of attraction between
objects due to gravity. Gravity is what keeps you and me on the ground.
In fact, gravity exists between you and your computer. You are attracted to
it by gravity. You don't feel the attraction because the computer's mass is so small.
The earth, on the other hand has a very large mass. That's why you are attracted to
the ground. Weight, unlike mass, changes with location. The farther you are from
the center of the Earth, the less you weigh. The
metric unit for weight is the
Newton, even though in America the most common unit is the pound. The equation
for weight is
Weight=Mass x Acceleration due to gravity(a).
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It is defined as a substance that cannot be further reduced to simpler substances by ordinary processes. Elements are made up of
particles/atoms of only one kind.
For example: Hydrogen and oxygen
There are
114 elements known. Out of these 92 of them occur in nature.
Classification of Elements
Elements can be further divided into Metals and Non-metals.
Metals
They are generally solids with characteristics such as hardness, malleability, ductility high tensile strength, lustre and ability to conduct heat and electricity.
For example: Copper, iron, zinc etc.
Physical Properties of Elements
Physical State
Metals are
solids at room temperature with the exception of mercury and gallium, which are liquids at room temperature.
Lustre
Metals have the quality of
reflecting light from its surface and can be polished e.g., gold, silver and copper.
Malleability
Metals have the ability to
withstand hammering and can be made into
thin sheets known as foils.
Ductility
Metals can be drawn into
wires. 100 gm of silver can be drawn into a thin wire about 200 meters long.
Hardness
All metals are
hard except sodium and potassium, which are soft and can be cut with a knife.
Valency
Metals have
1 to 3 electrons in the outermost shell of their atoms.
Conduction
Metals are
good conductors because they have free electrons.
Silver and copper are the two best conductors of heat and electricity. Lead is the poorest conductor of heat. Bismuth, mercury and iron are also poor conductors
Density
Metals have
high density and are very heavy.
Iridium and osmium have the
highest densities where as
lithium has the
lowest density.
Melting and Boiling Point
Metals have
high melting and boiling point.
Tungsten has the highest melting point where as
silver has low boiling point. Sodium and potassium have low melting points.
Electropositive Character
Metals are elements that have a tendency to
lose electrons and form cations. They normally do not accept electrons.
To Summarize:
Metals are electropositive in nature, lustrous, malleable, ductile, good conductors of heat and electricity and generally form basic or amphoteric oxides with oxygen.
Non-Metals
They are generally non-lustrous, brittle, poor conductors of heat and electricity.
For example: Sulphur, phosphorus, nitrogen etc
Physical Properties of Non-metals
Physical State
Most of the non-metals exist in two of the
three states of matter at room temperature: Gases (oxygen) and Solids (carbon). These have
no metallic lustre, and do not reflect light.
Nature
Non-metals are
very brittle, and cannot be rolled into wires or pounded into sheets.
Conduction
They are
poor conductors of heat and electricity.
Electronegative Character
Non-metals have a tendency to
gain or share electrons with other atoms. They are electronegative in character.
Reactivity
They generally form acidic or neutral oxides with oxygen.
Comparative Property of Metals & Non-Metals
Position of Metallic and Non-Metallic Elements in the Periodic Table
Metals: Metals occur on the
left hand side of the Periodic Table.
Non-metals: Non-metals occur on the
right hand side of the Periodic Table.
Semi-metals(metalloids): Semi-metals with properties in between metals and non-metals occur between these
two groups. (B, Si, Ge, As, Sb, Te).
Metalloids
These elements have
characteristics common to metals and non-metals.
For example: Arsenic, tin, bismuth etc.
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It is a pure substance that can be
decomposed into simpler substances by some suitable chemical technique.
A compound is formed by
combination of two or more elements in a definite proportion.
For example: Water is a compound of hydrogen and oxygen elements present in the ratio of 1:8
Properties of Compound
A compound
cannot be separated into its constituents by mechanical or physical means.
For example: If we bring a magnet near a sample of iron sulphide, the iron present in the iron sulphide cannot be separated.
Properties of a compound
differ entirely from those of its
constituent elements.
For example: Water is made up of hydrogen and oxygen. However, the properties of hydrogen and oxygen (both gases) are different from water (liquid). Hydrogen is combustible, oxygen is a supporter of combustion whereas water (made up of both hydrogen and oxygen) puts out a flame.
Energy changes are involved in the formation of a compound. For example, iron and sulphur reacts only when heat is supplied.
The constituent elements in a compound are in a
fixed proportion by weight. In
water,
hydrogen and oxygen are present in a fixed ratio of
1:8 by weight.
A compound is a
homogenous substance. That is it is
same throughout in
properties and composition.
A compound has a
fixed melting point and boiling point. For example, Ice melts at 0
oC.
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A Mixture is a material containing two or more elements or compounds that are in close contact and are mixed in any proportion. The components of a mixture can be separated by physical means.
For example, air, gun powder, etc.
Properties of Mixtures
A Mixture may be
homogenous or heterogeneous.
A homogenous mixture has a
uniform composition throughout its mass.
For example, sugar or salt dissolved in water, alcohol in water, etc.
A heterogeneous mixture
does not have a uniform composition throughout its mass. There are visible sharp boundaries.
For example: Oil and water, salt and sand, etc.
The constituents of a mixture can be
separated by physical means like
filtration, evaporation, sublimation and magnetic separation.
In the preparation of a mixture, energy is neither evolved nor absorbed.
A mixture has
no definite melting and boiling point.
The constituents of a mixture retain their original set of properties. For example, sulphur dissolves in carbon disulphide and a magnet attracts iron filings.
Types of Mixtures
Differences between Mixtures and Compounds
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There are three states- Solids, Liquids, and Gases.
Solids
Solids have the lowest potential energy of the three states. The particles in a solid
are strongly attracted to one another because the particles are held in a fairly rigid arrangement;
the solid keeps its shape. The fact that solids are practically incompressible suggests that their
particles are very closely packed. They are not free to move from one point to another in the solid.
However, they do vibrate in their positions and this vibration is a form of kinetic energy.
If a solid is heated, its particles begin to vibrate more strongly. Eventually most solids reach a
point at which their particles overcome the strong attractive forces, and break free from their fixed
positions to become a liquid.
Liquids
The particles of a liquid are held together by weak attractive forces.
The fact that liquids are slightly compressible indicates that there are small
spaces between the particles. The particles tend to remain together but are free to slide
around each other and move considerable distances. Liquids take the shape of the container
they are held in. Such movement from one point to another is called translation. At the same time,
the liquid particles are also vibrating as are the solid particles. When heated the particles translate
and vibrate more rapidly, until they overcome the weak attractive forces holding them together and become
a gas.
Gases
A gas expands to fill the container it is in. This suggests that the attractive forces
acting between its particles are very small or nonexistent. A gas is also easily compressed,
indicating that particles are widely separated. The particles vibrate and translate freely. Since
energy has been provided to break the attractive forces of both the solid and the liquid phases,
gases have the highest potential energy of the three states of matter.
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