Question

34 g of Ammonia is decomposed to _________ g of Nitrogen and _____ g of Hydrogen, _____ is the ratio of Hydrogen to Nitrogen by mass. The options in blanks are respectively

• A. 28, 3 and 28:3
• B. 14, 6 and 14:6
• C. 14, 3 and 14:3
• D. 28, 6 and 14:3

Answer 1

The correct option is D

28, 6 and 14:3

34g of Ammonia is decomposed to 28g of Nitrogen and 6g of Hydrogen, 14:3 is the ratio of Nitrogen to Hydrogen by mass.

Gram atomic masses of Hydrogen and Nitrogen are 1g, 14g respectively.

Since there are three Hydrogen atoms, total mass of Hydrogen atoms is 3.

So the mass ratio is (Nitrogen):(Hydrogen) = 14:3

Total mass of Ammonia is 34.

Mass of Nitrogen in 17g of Ammonia is 14g

The mass of Nitrogen in 34g of Ammonia is $\frac{14}{17}\times 34\Rightarrow$ 28 g

The mass of Hydrogen in 34g of Ammonia is $\frac{3}{17}\times 34\Rightarrow$ 6 g