How do we find the molecular mass of polyatomic ions plz answer fast, tomorrow is my test - Science - Atoms and Molecules

Question

How do we find the molecular mass of polyatomic ions?? plz
answer fast, tomorrow is my test

Urvashi Yadav · Accepted Answer

For polyatomic ions, we calculate formula mass
instead of molecular mass

Formula
mass:

An ionic compound contains ions and its
formula represents the ions present in the ionic compound Thus, the
molar mass of an ionic compound will be the formula mass of the
ionic compound, which is calculated by addition of atomic mass of
the ions present in the formula of the ionic compound An ionic
compound does not contain molecules but contains ions attracted to
each other by electrostatic force of
attraction

Formula mass of polyatomic
ions:

To find the formula mass of a polyatomic ion,
you simply find the molar mass of every element that makes up the
ion and add them together Do not forget to multiply the molar mass
if there are multiple atoms

For Example:

Find the molar mass of
NO3:

NO3 is made up of Nitrogen and
Oxygen

Molar mass of N = 14 0067

Molar mass of O = 15 9994

There are three atoms of
Oxygen,

So Molar mass of 3O = 3 * 15 9994 = 47
9982

Molar mass of NO3= 14 0067 + 47 9982 = 62
0049

So, formula mass of
NO3= 62 0049

How do we find the molecular mass of polyatomic ions?? plz answer fast, tomorrow is my test..