Only knowing the number of molecules?

Question

C7H5(NO2)3

How can I find out the number of grams, number of moles, and number of N atoms, by only knowing that there are 1.24x10^28 molecules?

Any help is greatly appreciated!!

Answer 1

There are 6.022*10^23 particles/mol

So divide the number of molecules you have and divide by this number to get moles. This is 20591.2 moles.

From there you can find out the number of grams knowing that each molecule is 227 grams/mol (just multiply the numbers).

You already know the number of moles. And just multiply the amount of molecules you have by 3 since there are 3 nitrogen atoms for every molecule. . 3.72*10^28 atoms of Nitrogen

Answer 2

First find the molecular mass of this molecule. C is 12.01, H is 1.01 N is 14.01 and O is 16.0 individually.  The total molecular mass is 227.15 amu.  This number also is equal to the wieght of grams in one mole of the compound. One mole of any compound is 6.022 x 10^23 atoms.  So in this case you have 2.06 x 10^4 moles. Wieght in grams is 4.67 x 10^6 grams.  The # of N atoms is simply 1.24 x 10^28  x  3 which equals 3.72 x 10^28.