Question

How will you prepare

a) A mixture of iron filings and sulphur

b) A compound formed by iron and sulphur

Answer 1

AIM
To prepare
(a) a mixture
(b) a compound using iron filings and sulphur powder and distinguish between these on the basis of:

appearance, i.e. homogeneity and heterogeneity
behaviour towards a management
behaviour towards carbon disulphide (a solvent)
effect of heat

MATERIALS REQUIRED
China dish, tripod stand, wire gauze, iron filings, sulphur burner, test tube stand and test tube holder.

THEORY
Formation of mixture is a physical change while formation of compound is a chemical change. Mixture may be homogeneous or heterogeneous while compounds are always homogeneous. In a mixture, components retain their individual properties while the components of a compound lose their individual properties. The components of a mixture can be separated by physical methods while the components of compounds cannot be separated by physical methods.

PROCEDURE
Preparation of mixture of iron and sulphur:
Take 7 g iron filing and 4 g sulphur powder in a petri dish and mix them properly. Label this mixture as A.

Preparation of compound iron sulphide:
Take 7 g iron filing and 4 g sulphur in a china dish. Heat this mixture gently and then strongly. Stir constantly till black mass or compound of iron and sulphur is formed.
Cool the content of china dish and powder the black mass. Label compound powder as B.

RESULT

‘A’ is a mixture which is prepared by mixing iron filings and sulphur.
‘B’ is a compound which is formed by strongly heating a mixture of iron filings and sulphur.


Mixture of iron filings and sulphur is heterogeneous while the compound iron sulphide is homogeneous.
Properties of FeS are different from the properties of its constituents.