Question

What is the percent composition of Ammonia, $N{H_3}$?

Answer 1

Hint : To solve this question, first calculate the molar mass of $N{H_3}$ by adding the individual mass of each atom. Use a periodic table if you need to check the atomic mass of each element. Divide the mass of each individual atom by the total mass of the molecule and then multiply it by $100$ to get the percent composition.

Complete Step By Step Answer:
Percent composition tells us what kind of elements are present in a molecule and their level in the molecule. Percent composition is used to find the mole-to-mole ratio of ions in a compound. This ratio is further used to determine the empirical formula of a compound and thus the molecular formula of the compound with covalent bonding.
Using a periodic table, first obtain the molar mass of $N{H_3}$ by adding the individual mass of nitrogen and hydrogen.
The atomic mass of nitrogen, $N$ is $14gmo{l^{ - 1}}$ while the atomic mass of hydrogen, $H$ is $1gmo{l^{ - 1}}$. In $N{H_3}$, there is one nitrogen atom and three hydrogen atoms. Hence the molar mass of $N{H_3}$ is,
$14 + 1 \times 3 = 17gmo{l^{ - 1}}$
Here, $17g$ of $N{H_3}$ contains $14g$ of nitrogen and $3g$ of hydrogen.
Now, let’s calculate the percent composition of nitrogen and hydrogen in $N{H_3}$.
The percent composition of nitrogen in $N{H_3}$ $= \dfrac{{14}}{{17}} \times 100 = 82.35\%$
The percent composition of hydrogen in $N{H_3}$ $= \dfrac{3}{{17}} \times 100 = 17.65\%$.
Hence, we can say that there is $82.35\%$ of nitrogen and $17.65\%$ of hydrogen in $N{H_3}$.

Note :
Percent composition plays an important aspect in everyday life. The most basic example of percent composition is the nutrition labels printed at the back of different food items. It is also used in testing the purity of a compound by comparing the percent composition with the theoretical value.