EXPERIMENTS
to carry out the following reactions and classify them as physical and chemical changes.
a).Iron with copper sulphate solution in water.
b.)burning of magnesiun in air
c.)zinc with dilute sulphuric acid
d.)heating of copper sulphate
e.)sodium sulphate with barium chloride in the form of their solutions in water
explain each activity one by one
please do chemical reactions
also
and tell about them briefly
you can also send answers photo
Answers
To carry out the following chemical reactions and classify them as physical or chemical changes.
Iron with copper sulphate solution in water.
Burning of magnesium ribbon in air.
Zinc with dilute sulphuric acid.
Heating of copper sulphate.
Sodium sulphate with barium chloride in the form of their solutions in water.
Theory
Physical Change: When there is no change in the composition of a substance and no change in chemical nature of the substance, such change is called as physical change.
In physical change, the interconversion of state takes place. For example,ncert-class-9-science-lab-manual-types-of-reactions-and-changes-1
Chemical Change: It is a change which brings change in the chemical properties of matter and a new substance is obtained. For example, burning of oil, fuel.
In a chemical change – heat is evolved or taken in, formation of bubbles, gas, fumes takes place, there is a change in colour of the reactants when they form a product.
Reactants\longrightarrow Products\\ A+B\longrightarrow C(Chemical\quad reaction)
The chemical reactions are of four types:
Combination reaction: Two elements/compounds combine to form a single product.
A+B\longrightarrow C\\ 2Mg(s)+{ O }_{ 2 }(g)\longrightarrow 2MgO(s)\\ CaO(s)+{ H }_{ 2 }O(l)\longrightarrow Ca{ (OH) }_{ 2 }(aq)
Decomposition reaction: When a compound decomposes/breaks due to energy, heat, light or electricity to form simpler substance.
ncert-class-9-science-lab-manual-types-of-reactions-and-changes-2
Displacement reaction: It takes place when more reactive metal reacts with the salt of less reactive metal and displaces it to form a new compound.
ncert-class-9-science-lab-manual-types-of-reactions-and-changes-3
Double displacement reaction: In this reaction when two salts are mixed together in solution form then exchange of ions takes place and a new product is obtained.
E.g.
ncert-class-9-science-lab-manual-types-of-reactions-and-changes-4
Materials Required
Test tubes, test tube stand, test tube holder, a pair of tongs, Bunsen burner.
Chemicals Required
Iron filings, copper sulphate solution, magnesium ribbon, zinc granules, dilute sulphuric acid, sodium sulphate and barium chloride solutions and copper sulphate crystals.
Procedure
Iron with copper sulphate solution in water
ncert-class-9-science-lab-manual-types-of-reactions-and-changes-5
Reactions of Fe+Cu{ SO }_{ 4 }
ncert-class-9-science-lab-manual-types-of-reactions-and-changes-6
Burning of magnesium ribbon in air
ncert-class-9-science-lab-manual-types-of-reactions-and-changes-7
Reaction of Mg\quad +\quad { O }_{ 2 }
ncert-class-9-science-lab-manual-types-of-reactions-and-changes-8
Zinc with dilute sulphuric acid.
ncert-class-9-science-lab-manual-types-of-reactions-and-changes-9
Reactions of Zn\quad +\quad { H }_{ 2 }S{ O }_{ 4 }
ncert-class-9-science-lab-manual-types-of-reactions-and-changes-10
Reaction: Zn(s)+Zn\quad +\quad { H }_{ 2 }S{ O }_{ 4 }\longrightarrow ZnS{ O }_{ 4 }(aq)+{ H }_{ 2 }(g)
Heating of copper sulphate salt
ncert-class-9-science-lab-manual-types-of-reactions-and-changes-11
Reaction of heat on CuS{ O }_{ 4 } crystals.
ncert-class-9-science-lab-manual-types-of-reactions-and-changes-12
Reaction of sodium sulphate and barium sulphate solutions.
ncert-class-9-science-lab-manual-types-of-reactions-and-changes-13
Reaction of N{ a }_{ 2 }S{ O }_{ 4 }+\quad BaC{ l }_{ 2 }
ncert-class-9-science-lab-manual-types-of-reactions-and-changes-14
Precautions
Use all the chemicals in very less quantity.
Use test tube holder for heating.
Clean magnesium ribbon with sand paper and use fire tongs for holding magnesium ribbon.
Handle the acids and alkalies carefully.
VIVA VOCE
Question 1:
Why is a chemical change called a chemical reaction?
Answer:
In chemical change, two or more substances react together to form a new product with new properties, so it is called a chemical reaction.
Question 2:
State four different types of chemical reactions.
Answer:
Combination reaction, decomposition reaction, displacement reaction and double displacement reaction.