# When 5 G of Calcium is Burnt in 2 G of Oxygen, Then 7 G of Calcium Oxide is Produced. What Mass of Calcium Oxide Will Be Produced When 5 G of Calcium is Burnt in 20 G of Oxygen ? Which Law of - Science

Short Note

When 5 g of calcium is burnt in 2 g of oxygen, then 7 g of calcium oxide is produced. What mass of calcium oxide will be produced when 5 g of calcium is burnt in 20 g of oxygen ? Which law of chemical combination will govern your answer ?

#### Solution

5g of calcium react with 2g of oxygen to form 7g of calcium oxide.

This problem can be solved using the law of constant proportions.

We know that calcium and oxygen react in a fixed ratio of 5:2, by mass, to produce 7g of calcium oxide. When 5g of calcium react with 20g of oxygen, the same amount of calcium oxide will be formed.

Therefore, 7g of calcium oxide will be formed when 5g of calcium will react with 20g of oxygen. Calcium and oxygen will react in a ratio of 5:2. The remaining oxygen will remain unreacted.

The law of constant proportions governs our answer.

Concept: Laws of Chemical Combination - Law of Constant Proportions or Law of Definite Proportions
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#### APPEARS IN

Lakhmir Singh Class 9 Chemistry - Science Part 2
Chapter 3 Atoms and Molecules
Hots Questions | Q 79 | Page 132