Question

In a china dish when iron fillings and sulphur powder are mixed together then,
a)a homogeneous mixture is formed
b)a heterogeneous mixture us formed
c)a compound is formed
d)physical properties of iron and sulphur are changed

Answer 1

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 heterogeneitybehaviour towards a managementbehaviour 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.

PROCEDURE, OBSERVATION AND INFERENCE

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. The chemical equation for this change is as follows:
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.

PRECAUTIONS

Handle the chemicals carefully.Do not bring CS2 near the flame as it is highly inflammable.Heating of mixture of iron filing and sulphur should be done in china dish.Wash your hands properly with soap after the experiment.