1
Sunil Sureka
2. is matter around us pure
1. Give a chart showing different categories of matter.
Matter
Pure Substances Mixtures
Elements Compounds Homogeneous Heterogeneous
Metals
Metalloids
Non-Metals
2. Define the followings:
a) Pure substance
A pure substance is one which is made up of only one kind of particles. These
particles may be atoms or molecules.
E.g.: Hydrogen, Water
Characteristics:
A pure substance is homogeneous throughout its mass.
A pure substance cannot be separated into other kinds of matter by any physical
process.
A pure substance has a fixed composition.
A pure substance has a fixed melting and boiling point.
b) Elements
An element is a substance, which cannot be split up into two or more simpler
substance by the usual chemical methods of applying heat, light or electric energy.
E.g.: Iron (Fe), Copper (Cu), Oxygen (O2) etc
Characteristics:
All the atoms of an element are identical.
The atoms of different elements differ in size and composition.
Elements can be solid, liquids or gases.
All the elements can be divided into three groups – metals, non-metals and
metalloids.
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Sunil Sureka
c) Metals
A metal is an element that is malleable, ductile and conducts electricity.
E.g.: Iron (Fe), Copper (Cu), Zinc (Zn) etc.
d) Metalloids
The elements which show some properties of metals and some other properties of
non-metals are called metalloids.
E.g.: Boron (B), Silicon (Si), Germanium (Ge), Arsenic (As), Antimony (Sb), Tellurium (Te),
Polonium (Po) and Astatine (At)
e) Non-metals
A non-metal is an element that is brittle and does not conduct electricity.
E.g.: Carbon (C), Sulphur (S), Phosphorus (P) etc.
f) Compounds
A compound is a substance made up of two or more elements, chemically combined
in fixed proportion by mass.
E.g.: Water (H2O), Sodium Chloride (NaCl), Sand or Silica (SiO2), Marble (CaCO3), Ammonia
(NH3), Ice (H2O), chalk (CaCO3), limestone (CaCO3), lime or Quick lime (CaO), slaked lime
{Ca(OH)2} etc.
Characteristics:
A compound is formed as a result of a chemical change.
Energy in the form of heat or light is usually either evolved or absorbed during the
preparation of a compound.
A compound is always made up of the same elements, combined together in fixed
proportion by mass.
A compound has a definite molecular formula.
The properties of a compound are entirely different from those of its constituent
elements.
A compound has fixed melting and boiling point.
A compound is a homogeneous substance.
A compound cannot be separated into its constituents by simple physical methods.
Compound are of three types: acid, base and salt
g) Mixtures (Impure Substances)
A mixture is one which contains two or more different kinds of particles. These
particles may be atoms or molecules.
E.g. Salt solution, Milk
Characteristics:
A compound is not formed as a result of a chemical change.
Energy is neither evolved nor absorbed during the preparation of a mixture.
The composition of a mixture is variable and constituents can be present in any
proportion by mass.
A mixture does not have a definite molecular formula.
The properties of a mixture are the properties of its constituents.
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Sunil Sureka
A mixture does not have a fixed melting and boiling point.
A mixture can be separated into its constituents by simple physical method.
A mixture is usually heterogeneous (except – true solutions and alloys, which are
homogeneous mixtures)
h) Homogeneous Mixture
A mixture is said to be homogeneous, if all the components of the mixture are
uniformly mixed and are indistinguishable from one another are called homogenous mixture.
E.g.: Salt
solution, Sea water, Air, Alloys etc
A homogeneous mixture has uniform composition and properties throughout its mass.
A homogeneous mixture is called solution (or true solution).
A homogeneous mixture has no distinct boundaries of separation, i.e. it consists of only one
phase, which may be solid, liquid or gaseous.
i) Heterogeneous Mixture
A mixture is said to be heterogeneous, if all the components of the mixture are not
uniformly mixed and are distinguishable from one another are called heterogeneous mixtures.
E.g.: mixture of
petrol and water, mixture of sand in water, gun powder, iodized salt etc.
A heterogeneous mixture has non-uniform composition and different properties throughout
its mass.
A heterogeneous mixture is a suspension of solids in liquids.
A heterogeneous mixture has distinct boundaries of separation, i.e. it consists of two or more
phases, which can either be solids or liquids, but not gaseous.
3. Compare the properties of metals and non-metals
Sl.No Metals Non-metals
Metals are malleable. Non-metals are brittle.
i.
Gold and silver are most malleable metals
Metals are ductile Non-metals are non-ductile
ii.
Gold and silver are most ductile metals
Metals are good conductors of heat and Non metals are bad conductors of heat
electricity. and electricity
Silver is the best conductor of heat and Exception-
iii.
electricity a. Diamond is a good conductor of heat.
b. Graphite is a good conductor of
electricity.
Metals are lustrous Non-metals are non-lustrous.
iv.
Silver is an excellent reflector of light Exception - Diamond, graphite and iodine
Metals are generally hard Non-metals are generally soft.
v. Exception - sodium and potassium are soft. Exception - Diamond is the hardest natural
substance known
Metals are usually strong and have high Non-metals are not strong and have low
vi.
tensile strength tensile strength.
Sunil Sureka
2. is matter around us pure
1. Give a chart showing different categories of matter.
Matter
Pure Substances Mixtures
Elements Compounds Homogeneous Heterogeneous
Metals
Metalloids
Non-Metals
2. Define the followings:
a) Pure substance
A pure substance is one which is made up of only one kind of particles. These
particles may be atoms or molecules.
E.g.: Hydrogen, Water
Characteristics:
A pure substance is homogeneous throughout its mass.
A pure substance cannot be separated into other kinds of matter by any physical
process.
A pure substance has a fixed composition.
A pure substance has a fixed melting and boiling point.
b) Elements
An element is a substance, which cannot be split up into two or more simpler
substance by the usual chemical methods of applying heat, light or electric energy.
E.g.: Iron (Fe), Copper (Cu), Oxygen (O2) etc
Characteristics:
All the atoms of an element are identical.
The atoms of different elements differ in size and composition.
Elements can be solid, liquids or gases.
All the elements can be divided into three groups – metals, non-metals and
metalloids.
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Sunil Sureka
c) Metals
A metal is an element that is malleable, ductile and conducts electricity.
E.g.: Iron (Fe), Copper (Cu), Zinc (Zn) etc.
d) Metalloids
The elements which show some properties of metals and some other properties of
non-metals are called metalloids.
E.g.: Boron (B), Silicon (Si), Germanium (Ge), Arsenic (As), Antimony (Sb), Tellurium (Te),
Polonium (Po) and Astatine (At)
e) Non-metals
A non-metal is an element that is brittle and does not conduct electricity.
E.g.: Carbon (C), Sulphur (S), Phosphorus (P) etc.
f) Compounds
A compound is a substance made up of two or more elements, chemically combined
in fixed proportion by mass.
E.g.: Water (H2O), Sodium Chloride (NaCl), Sand or Silica (SiO2), Marble (CaCO3), Ammonia
(NH3), Ice (H2O), chalk (CaCO3), limestone (CaCO3), lime or Quick lime (CaO), slaked lime
{Ca(OH)2} etc.
Characteristics:
A compound is formed as a result of a chemical change.
Energy in the form of heat or light is usually either evolved or absorbed during the
preparation of a compound.
A compound is always made up of the same elements, combined together in fixed
proportion by mass.
A compound has a definite molecular formula.
The properties of a compound are entirely different from those of its constituent
elements.
A compound has fixed melting and boiling point.
A compound is a homogeneous substance.
A compound cannot be separated into its constituents by simple physical methods.
Compound are of three types: acid, base and salt
g) Mixtures (Impure Substances)
A mixture is one which contains two or more different kinds of particles. These
particles may be atoms or molecules.
E.g. Salt solution, Milk
Characteristics:
A compound is not formed as a result of a chemical change.
Energy is neither evolved nor absorbed during the preparation of a mixture.
The composition of a mixture is variable and constituents can be present in any
proportion by mass.
A mixture does not have a definite molecular formula.
The properties of a mixture are the properties of its constituents.
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Sunil Sureka
A mixture does not have a fixed melting and boiling point.
A mixture can be separated into its constituents by simple physical method.
A mixture is usually heterogeneous (except – true solutions and alloys, which are
homogeneous mixtures)
h) Homogeneous Mixture
A mixture is said to be homogeneous, if all the components of the mixture are
uniformly mixed and are indistinguishable from one another are called homogenous mixture.
E.g.: Salt
solution, Sea water, Air, Alloys etc
A homogeneous mixture has uniform composition and properties throughout its mass.
A homogeneous mixture is called solution (or true solution).
A homogeneous mixture has no distinct boundaries of separation, i.e. it consists of only one
phase, which may be solid, liquid or gaseous.
i) Heterogeneous Mixture
A mixture is said to be heterogeneous, if all the components of the mixture are not
uniformly mixed and are distinguishable from one another are called heterogeneous mixtures.
E.g.: mixture of
petrol and water, mixture of sand in water, gun powder, iodized salt etc.
A heterogeneous mixture has non-uniform composition and different properties throughout
its mass.
A heterogeneous mixture is a suspension of solids in liquids.
A heterogeneous mixture has distinct boundaries of separation, i.e. it consists of two or more
phases, which can either be solids or liquids, but not gaseous.
3. Compare the properties of metals and non-metals
Sl.No Metals Non-metals
Metals are malleable. Non-metals are brittle.
i.
Gold and silver are most malleable metals
Metals are ductile Non-metals are non-ductile
ii.
Gold and silver are most ductile metals
Metals are good conductors of heat and Non metals are bad conductors of heat
electricity. and electricity
Silver is the best conductor of heat and Exception-
iii.
electricity a. Diamond is a good conductor of heat.
b. Graphite is a good conductor of
electricity.
Metals are lustrous Non-metals are non-lustrous.
iv.
Silver is an excellent reflector of light Exception - Diamond, graphite and iodine
Metals are generally hard Non-metals are generally soft.
v. Exception - sodium and potassium are soft. Exception - Diamond is the hardest natural
substance known
Metals are usually strong and have high Non-metals are not strong and have low
vi.
tensile strength tensile strength.
