In this experiment, we shall learn to prepare a mixture and compound. Before that, we will revise the concepts in brief.
1. When two or more elements react together, they form a compound.
2. The properties of the new substance formed are different from the properties of substances that react.
3. The composition can only be separated through a chemical reaction.
1. When two or more elements mix together, they form a mixture.
2. No new element or compound is formed.
3. The properties of the new substance formed are the same as the properties of substances mixed.
4. The composition can be separated through physical processes.
a) a compound,
b) a mixture,
Using sulphur powder and iron fillings.
Distinguish these based on a) appearance, i.e., heterogeneity and homogeneity,
b) behaviour towards management,
c) behaviour towards sulphur dioxide,
d) effect of heat.
1. Tripod stand,
2. China dish,
3. Wire gauge,
4. Iron fillings,
5. Test tube,
6. Sulphur burner,
7. Test tube holder.
1. Formation of the compound is a chemical process. It is always homogeneous in nature. This can only be separated through a chemical process.
2. Formation of the mixture is a physical process. It can be homogeneous or heterogeneous. This can be separated through a physical process.
1. PREPARATION OF MIXTURE OF IRON AND SULPHUR:
Take 4g of sulphur powder and 7g of iron filling in a test tube and mix them properly. Label this as mixture A.
2. PREPARATION OF IRON SULPHIDE COMPOUND:
Take 4g of sulphur and 7g of iron filling in a china dish and heat it strongly. Mix this mixture until a black compound of sulphur and iron is formed.
Cool the content and powder the black compound. Label this as B.
i) Put a small quantity of mixture A in a watch glass and stir it well with a glass rod.
ii) Put a small quantity of black compound B in a watch glass and stir it well with a glass rod.
|Sulphur particles and iron filling particles are visible through naked eyes.
Every portion of the black compound appears the same.
|A heterogeneous mixture is obtained when sulphur is mixed with iron fillings.
A homogenous FeS mixture is formed when iron filling and sulphur are heated.
Behaviour towards Magnet
i) Move a bar magnet over mixture A.
ii) Move a bar magnet over mixture B.
|The iron filling is attracted to the bar magnet.||Iron retained its magnetic nature in a mixture.
Iron loses its magnetic nature in a compound.
Behaviour towards Carbon Disulphide
i) Take a small amount of mixture A in a test tube. Add a small amount of carbon disulphide and stir well.
ii)Take a small amount of mixture B in a test tube. Add a small amount of carbon disulphide and stir well.
|A yellow solution forms when sulphur dissolves in CS2. When CS2 is evaporated, solid sulphur reappears.
No change occurs in the test tube.
|In a mixture, components can be separated through a physical process.
In a compound, Components can’t be separated through a physical process.
Effect of Heat
i) Take a small amount of mixture A and heat it.
ii) Take a small amount of mixture A and heat it.
|A black substance is formed while heating.
No change took place.
|A new compound is formed by heating iron and sulphur.
Iron sulphide does not lose its properties on heating.
1. “A” is a mixture obtained by mixing sulphur and iron fillings.
2. “B” is iron sulphide obtained by heating sulphur powder and iron filling.
Fe + S → FeS
( black powder)
3. Heterogeneous mixture is formed by mixing iron and sulphur.
4. Homogenous mixture is formed by heating sulphur and iron.
5. The properties of constituents are different from the property of Fes.
1. Always keep a distance while performing any experiment.
2. Keep your eyes away from the test tube.
3. Forbid bringing CS2 near flame.
4. Remember to wash your hands after the experiment.
In this way, we have obtained a mixture and compound and seen their properties.
Q.1 Why we should not bring CS2 near flame?
ANS. Because CS2 is highly combustible, i.e., catches fire easily.
Q.2 What do you mean by a mixture?
ANS. When two or more elements mix together, they form a mixture.
Q.3 What do you mean by a compound?
ANS. Compounds are formed when two or more elements react together.
Q.4 What is the name of the compound CS2?
Q.5 Write the chemical reaction of iron and sulphur?
ANS. Fe + S → FeS
( black powder)
Q.6 What is the nature of FeS formed?
ANS. FeS is Homogenous and has properties different from its constituent.
Q.7 What are the examples of a mixture?
ANS. Water in alcohol, sugar in water etc.
Q.8 What are the examples of compounds?
ANS. Water, sugar, methane etc.
Q.9 How many types of the mixture are there?
ANS. Two. Homogenous and heterogeneous.
Q.10 What do you understand by homogeneous and heterogeneous?
ANS. Homogeneous mixtures are those mixtures that have uniform composition.
Heterogeneous mixtures are those mixtures that have non-uniform composition.
An Indian nuclear physicist, founding director, and professor of physics at the Tata Institute of Fundamental Research.