Balance the following chemical equation: FeS + O 2 → Fe 2 O 3 + SO 2

Iron sulphide undergoes oxidation to form Ferric oxide and the liberation of Sulphur dioxide. The balanced equation is written as: 4 FeS + 7 O 2 → 2 Fe 2 O 3 + 4 SO 2 For the balancing of reaction the number of atoms of each element on each side should be equal.

Balance the following chemical equation: Na + Cl 2 → NaCl

A balanced chemical equation should contain equal number of atoms on both the sides of the equation. That is, it should obey the law of conservation of mass. The given reaction represents the combination reaction of sodium and chlorine to form sodium chloride. It can be balanced as 2 Na + Cl 2 → 2 NaCl

Balance the following chemical equation: CO 2 + Ca OH 2 → CaCO 3 + H 2 O

A balanced chemical equation should contain an equal number of atoms on both the sides of the equation. That is, it should obey the law of conservation of mass. The given reaction represents the reaction between calcium hydroxide and carbon dioxide. It can be balanced as CO 2 + Ca OH 2 → CaCO 3 + H 2 O

E M B I B E

The Science Hub>Chapter 4 - Chemicals and Chemical Changes>Breather>Q (d)

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7th CBSE

IMPORTANT

Earn 100

Write the valency of the following element

Calcium

Important Questions on Chemicals and Chemical Changes

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7th CBSE

IMPORTANT

The Science Hub>Chapter 4 - Chemicals and Chemical Changes>Breather>Q (e)

Write the valency of the following element

Copper

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IMPORTANT

The Science Hub>Chapter 4 - Chemicals and Chemical Changes>Breather>Q (f)

Write the valency of the following element

Oxygen

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IMPORTANT

The Science Hub>Chapter 4 - Chemicals and Chemical Changes>Breather>Q (a)

Balance the following chemical equation:

$FeS + O_{2} \to {Fe}_{2} O_{3} + {SO}_{2}$

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7th CBSE

IMPORTANT

The Science Hub>Chapter 4 - Chemicals and Chemical Changes>Breather>Q (b)

Balance the following chemical equation:

$Na + {Cl}_{2} \to NaCl$

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7th CBSE

IMPORTANT

The Science Hub>Chapter 4 - Chemicals and Chemical Changes>Breather>Q (c)

Balance the following chemical equation:

${CO}_{2} + Ca {(OH)}_{2} \to {CaCO}_{3} + H_{2} O$

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7th CBSE

IMPORTANT

The Science Hub>Chapter 4 - Chemicals and Chemical Changes>Life Skills

It is Diwali time. Rajat is having school holidays. He wants to help his parents with the work at home. He noticed that the iron grills of the windows have turned reddish-brown and are looking bad. So he asks his father what they could do to make them look good again. What suggestion will you give to Rajat? Why?

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The Science Hub>Chapter 4 - Chemicals and Chemical Changes>Values

Manisha was at home on account of school holiday. In the evening when her father returned from work, she decided to prepare a cup of tea for him. She poured hot boiling tea in a glass cup and the cup cracked. She was upset but her father consoled her and told her the reason of the cup cracking. What was the reason? What kind of change is it?

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IMPORTANT

The Science Hub>Chapter 4 - Chemicals and Chemical Changes>Exercises>Q 1

Melting of butter is a physical change.