3. Atoms and Molecules – Class 9 Science | NCERT Chapter-wise Important Questions and Answers (CBSE)

Chapter 3: Atoms and Molecules – Class 9 Science NCERT | Chapterwise Important Questions and Answers (CBSE)

Chapter 3: Atoms and Molecules

Internal Questions:

1. In a reaction, 5.3 g of sodium carbonate reacted with 6 g of acetic acid. The products were 2.2 g of carbon dioxide, 0.9 g water and 8.2 g of sodium acetate. Show that these observations are in agreement with the law of conservation of mass.
     sodium carbonate + acetic acid → sodium acetate + carbon dioxide + water

Solution: We have,

Sodium carbonate (Na2CO3) + Acetic acid (CH3COOH) → Sodium acetate (CH3COONa) + Carbon dioxide (CO2) + Water (H2O)

Here, Sodium carbonate (Na2CO3) = 5.3 g

 Acetic acid (CH3COOH) = 6 g

 Sodium acetate (CH3COONa) = 8.2 g

 Carbon dioxide (CO2) = 2.2 g

 Water (H2O) = 0.9

LHS : Sodium carbonate (Na2CO3) + Acetic acid (CH3COOH)

= 5.3 g + 6 g

=11.3 g

RHS : Sodium acetate (CH3COONa) + Carbon dioxide (CO2) + Water (H2O)

= 8.2 g + 2.2 g + 0.9 g

=11.3 g

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Posted 4 months ago