Question

C. Fill in the blank.

1.Heat is absorbed during______ reaction.
2. Coating iron articles with zinc is called_______.
3._______changes are irreversible and permanent.
4. Corrosion of iron is called_______.
5. Rusting makes the iron object______.
6. Making mixture is a______change.
7. Photosynthesis is a ________ change.
8. Electrolysis of water gives_____and_____gases.

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Answer 1

✳Answers✳

1.Heat is absorbed during Exothermic reaction.

2. Coating iron articles with zinc is called Galvanization.

3.Chemical changes are irreversible and permanent.

4.Corrosion of iron is called Rusting.

5.Rusting makes the iron objects Fragile.

6.Making mixture is a Physical change.

7.Photosynthesis is a chemical change.

8.Electrolysis of water gives Hydrogen and Oxygen gases.

CHEMICAL AND PHYSICAL CHANGES

✳Physical Changes✳

• It is a temporary change.
• No new products are formed.
• No energy is produced.
• It is a reversible change.
• Examples :- Melting of Ice , Dissolving of salt in water , etc.

✳Chemical Changes✳

• It is permanent change.
• New products are formed.
• Energy is produced.
• It is an irreversible change.
• Examples:- Ripening of Fruits, Burning of crackers , Digestion of food etc.

Answer 2

Fill in the blanks :-

1. Heat is observed during __________ reaction.

2. Coating iron articles with zinc is called ____________.

3. ________ changes are irreversible and permanent.

4. Corrosion of iron is called _______.

5. Rusting makes the iron object _______.

6. Making mixture is a ________ change.

7. Photosynthesis is a ________ change.

8. Electrolysis of water gives ________ and ______ gases.

Answer :-

1. Heat is absorbed during $\underline{\bf\purple{exothermic}}$reaction.

2. Coating iron articles with zinc is called $\underline{\bf\pink{galvaniztiom}}$.

3. $\underline{\bf\purple{Chemical}}$ changes are irreversible and permanent.

4. Corrosion of iron is called $\underline{\bf\pink{rusting}}$.

5. Rusting makes the iron objects $\underline{\bf\purple{fragile}}$.

6. Making mixture is a $\underline{\bf\pink{physical}}$change.

7. Photosynthesis is a $\underline{\bf\purple{chemical}}$change.

8. Electrolysis of water gives $\underline{\bf\pink{hydrogen}}$and $\underline{\bf\purple{oxygen}}$gases.

$~~~~~~~~~~~~~~$ _____________________

$~~~~~~~~~~~~~~$ $\large\dag$Chemical change :

$~~~~~~~~~~~~~~~~~~~~~~~~~~~~$ and

$~~~~~~~~~~~~~~$ $\large\dag$ Physical change :

$~~~~~~~~~~~~~~$ _____________________

$\underline{\bf{Chemical~change :}}$

• Not easily revered.
• New Product ( s ) formed.
• Reactants used up.
• Often : heat / light / sound / fizzing occurs.
• Electricity may be produced.
• A precipitate may from.
• E.g., Wood burning.

$\underline{\bf{Physical~change :}}$

• Easily reversible.
• It is a temporary change.
• No new products.
• No new products are formed.
• Often just a state change.
• No energy is produced.
• E.g., ice melting.