Matter:Matter be defined as 'anything which occupies space and has mass and can be felt by one or more of our senses such as sight,touch,smell,hearing and taste.
There are two ways of classifying matter:
(1).physical classification.
(2).chemical classification.
(1).Physical classification: Based on physical state and under ordinary conditions of temperature and pressure,matter is classified into three states,namely:
(a)solids (b)liquids and (c)gases
(2).Chemical classification: On the basis of its chemical composition,matter may be classified into three broad types i.e.,elements,compounds and mixtures.
(2).Chemical classification: On the basis of its chemical composition,matter may be classified into three broad types i.e.,elements,compounds and mixtures.
Elements:
An elements may be defined as:The simplest form of a pure substance which can neither be decomposed into nor built up from simpler substances by ordinary physical and chemical methods.
Carbon, sulphur, iron,lead,gold,oxygen,hydrogen and nitrogen etc.,are common examples of elements.
Elements are further classified into three types:
(1).metals.
(2).non-metals.
(3).metalloids.
Compounds:
A compound is also a pure substance containing two or more elements.
The important properties of compound are:
(1).A compound has different properties from those of the elements of which it is composed of.
For example, water is a compound of hydrogen and oxygen but properties of water are entirely different from those of hydrogen and oxygen.
(2).A compound can only be split up into its elements by some chemical change.for example,
water can be split into hydrogen and oxygen by passing electricity through it by the addition of a few drops of an acid.
The compound have been classified into two types.These are:
(a).Inorganic compounds:These are the compounds which are obtained from minerals and rocks.
for example,common salt(nacl),marble (caco3)and washing soda (na2co3)etc.
(b).Organic compound:These are the compound which are obtained from plants and animals.
For example,carbohydrates,oils,fats,proteins and waxes etc.Mixtures
Mixture:A mixture may be defined as:
The combination of two or more elements or compounds in any proportion is called a mixture.
For example,
(1).Air is a gaseous mixture of o2,n2,co2,water vapours and noble gases etc.
(2).Tap water is a mixture of water,cahco3 and mgcl2 etc.
(3).Milk is a mixture of water,Fat,proteins and lactose etc.and
(4).Iodized table salt is mixture of nacl and a small amount 'nai'
A mixture has the following important characteristics:
(1).The properties of a mixture are midway between those of its constituents.For example,air is a mixture of nitrogen and oxygen and its properties lie midway between nitrogen and oxygen.
(2).A mixture can be separated by simple physical or mechanical methods. For example,a mixture of iron filings and sand can be easily separated by moving a magnet in the mixture.Iron filings stick to the magnet and is left behind.
Mixture are two types:
(a).Homogeneous mixtures and
(b).Heterogeneous mixtures
(a). Homogeneous mixture: A mixture is said to be homogeneous if its composition is uniform throughout.For example,if some sugar is dissolved in water, we get a homogeneous mixture or solution.Homogeneous mixtures are single phase mixtures.
(b) Heterogeneous Mixture: A mixture is said to be heterogeneous if its composition is not uniform throughout.
Difference between compounds and mixtures:
Compound:
(1).The constituents of a compound are always present in a fixed ratio by mass.(2).Compound are always homogeneous.
(3).The properties of a compound is quite different from those of its constituents.
(4).Compounds possess sharp melting and boiling points.
(5).The formation of a compound generally leads to the evolution or absorption of heat,light or electrical energy.
(6).Compound is formed as a result of chemical change.
(7).Its constituents can not be separated by simple mechanical means.
Mixtures:
(1).The constituents of a mixture may be present in any ratio.
(2).A mixture may or may not be homogeneous.
(3).The properties of the mixtures are midway between those of constituents.
(4).Mixtures usually do not possess sharp melting and the boiling points.
(5).When a mixture is formed,no heat,light or electrical energy is evolved or absorbed.
(6).Mixture is formed as a result of physical change.
(7).Its constituents can be separated by simple mechanical means.