Posted by jaz on .
Determine the number of moles of each specified atom or ion in the given samples of the following compunds.( Hint: the formula tells you how many atoms or ions are in each molecule of formula unit.)
a. O atom in 3.161x10^21 molecules of CO2
b. C atom in 3.161x10^21 molecules of CO2
c. O atom in 2.2222x10^24 molecules of CO2

chemistry help 
DrBob222,
You need to know one piece of information for these problems. That is as follows:
There are 6.02 x 10^23 atoms in a mole of atoms or 6.02 x 10^23 molecules in a mole of molecules (actually there are 6.02 x 10^23 in a mole of anything).
So in 3.161 x 10^21 molecules of CO2 there are 3.161 molecules x (1 mole CO2/6.02 x 10^23 molecules CO2)= ?? moles CO2. Then multiply that by 2 to find the moles of O in CO2.
The others are done th same way. 
chemistry help 
jaz,
si this is how you do a correct

chemistry help 
Greg,
45