Question

What NUMBER of carbon monoxide molecules constitutes a mass of `28*g`?

Answer 1

How many moles of `CO` do you have.........?

Explanation:

And we know that by definition, `1*mol` of stuff contains `6.022xx10^23` individual items of that stuff, i.e. `N_A` individual items, where `N_A-=6.022xx10^23*mol^-1`.

.......And here your stuff is `CO`, where a mole of said stuff has a mass of `28*g`....

How many atoms in this molar quantity?

Note that this question is effectively asking `"how many atoms are there in dozen carbon monoxide molecules?"`

I make it `"3 dozen.."`

If you can answer this question, you can certainly answer the former.