Question

How do you find the formula mass of ammonium carbonate ${(N{H_4})_2}C{O_3}$

Answer 1

In order to find the formula mass of ammonium carbonate ${(N{H_4})_2}C{O_3}$, we must first know what a formula mass is. Formula mass is said to be the sum of the atomic weight of the atoms which are present in the empirical formula of the given compound.

Complete answer:
Let us first understand about the formula mass of a compound. Formula mass is said to be the sum of the atomic weight of the atoms which are present in the empirical formula of the given compound.
Now let us move onto the problem given. Now we have to write the chemical elements present in the chemical formula of Ammonium carbonate, which are N, H, C and O.
From the periodic table, we have to give the formula mass of each elements, that is
N = 14 $gmo{l^{ - 1}}$
H = 1 $gmo{l^{ - 1}}$
C = 12 $gmo{l^{ - 1}}$
O = 16 $gmo{l^{ - 1}}$
From the molecular formula, we have to find the total number of each element present. There will be 2 nitrogen atoms, 8 hydrogen atoms, 1 carbon atom and 3 oxygen atoms.
Now multiply the total number of each chemical element with the formula mass of the element.
Now we will get,
Formula mass of Nitrogen = $14 \times 2 = 28gmo{l^{ - 1}}$
Formula mass of Hydrogen = $1 \times 8 = 8gmo{l^{ - 1}}$
Formula mass of Carbon = $12 \times 1 = 12gmo{l^{ - 1}}$
Formula mass of Oxygen = $16 \times 3 = 48gmo{l^{ - 1}}$
Finally add all these masses to obtain the formula mass of the ammonium carbonate.
i.e., $28 + 8 + 12 + 48 = 96gmo{l^{ - 1}}$
therefore, the formula mass of ammonium carbonate is found to be $96gmo{l^{ - 1}}$

Note:
We have to always remember that the formula mass and molar mass are not the same. They are different from each other as the Molar mass is said to be the mass of one mole of the substance, while the formula mass is said to be the sum of the atomic weight of the atoms present in the empirical formula of the compound.