Question

Find the ratio by mass of the combining elements in ammonia:
A.$N{H_3}:14:3$
B.$N{H_3}:3:14$
C.$N{H_4}:14:3$
D.$N{H_4}:7:3$

Answer 1

We can solve this question by finding the ratio of mass of the two elements in the ammonia molecule. Ammonia is formed from nitrogen and hydrogen so first we will find the mass of nitrogen and hydrogen in the molecule. We will multiply the atomic mass of the elements with the number of atoms of the elements present in the molecule. Then put the values in the formula-
$\Rightarrow$ Formula: mass of nitrogen in the molecule: mass of hydrogen in the molecule

Complete step by step answer:
We have to find a ratio of mass of combining elements of ammonia.
We know that the chemical formula of ammonia is$N{H_3}$. So from the formula it is clear that ammonia is made up of two elements- Nitrogen and Hydrogen.
First we will find the mass of the two elements in the ammonia molecule.
For this, we will multiply the atomic mass of the elements with the number of atoms of the elements present in the molecule.
We know that the atomic number of nitrogen is $7$ and its atomic mass is $14$
And in $N{H_3}$, only one atom of nitrogen is present so we get-
$\Rightarrow$ The mass of Nitrogen in the molecule =$14$ -- (i)
Now we know that the atomic number of hydrogen is $1$ and its atomic mass is also$1$.
And in$N{H_3}$, three atoms of hydrogen are present so the mass of Hydrogen in the molecule=$3 \times 1$
So we get-
$\Rightarrow$ Mass of Hydrogen in the molecule=$3$--- (ii)
Now we will put these values in the ratio-
$\Rightarrow$ Formula: mass of nitrogen in the molecule: mass of hydrogen in the molecule
On putting the values we get-
$\Rightarrow N{H_3}:14:3$

The correct answer is option A.

Note:
Ammonia is used for many purposes, some of which are-
-It is used as a refrigerant gas.
-It is used in purification of water supplies.
-It is used in manufacturing of plastics, textiles and pesticides.
-It is also used to make explosives.
-It is used in cleaning solutions.