Chapter 3 Atoms AND Molecules

NCERT Class 9th

Science SOLUTIONS

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Question

When 3.0 g of carbon is burnt in 8.00 g of oxygen, 11.00 g of carbon dioxide is produced. What mass of carbon dioxide will be formed when 3.00 g of carbon is burnt in 50.00 g of oxygen? Which law of chemical combination will govern your answer?

Updated on November 6, 2025 | By Learnzy Admin | 👁️ Views: 17 students

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Solution

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From the data:
3.0 g of carbon + 8.0 g of oxygen ----> 11.0 g of carbon dioxide

This means 3 g of carbon requires 8 g of oxygen to form 11 g of carbon dioxide.

Now, if 3 g of carbon is burnt in 50 g of oxygen, carbon is the limiting reactant because it can combine only with 8 g of oxygen. The remaining oxygen will be left unused.

So, the amount of carbon dioxide formed will still be 11 g.

Mass of carbon dioxide formed = 11.0 g

Law governing the reaction:
This is governed by the Law of Constant Proportion, which states that a chemical compound always contains the same elements in the same fixed ratio by mass.

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