No, you don't need to use Avogadro's number.
Here is a hint:
How many atoms are in each molecule of C7H5(NO2)3 ? (It is a number larger than 20)
Multiply that number by the number of molecules.
How many atoms are present in a sample of 2.0 x 10^23 molecules of C7H5(NO2)3?
Do you use Avogadro's Number?
And please show work.. :)
3 answers
Ohh~ Thanks! I got it now! So it's going to be 21 x 2.0 x 10^23 = And so I got 4.2 x 10^24 atoms (:
That's right!