Convert 1.65 * 1024 atoms of carbon to moles of carbon.

The number of moles in a substance indicates the amount of the substance that contains the same number of particles as 12 g of the Carbon-12 isotope [or equivalent to 6.02 * 10²³] (which is used as a standard in the world of moles).

Now,

if 6.02 * 10²³ atoms are found in 1 mole of C

then let 1.65 * 10²⁴ atoms are found in x

⇒ x = (1.65 * 10²⁴) : (6.02 * 10²³)

= 2.7409 mol

A sample of 1.65 * 10 ²⁴ atoms of Carbon (C) would contain ~ 2.74 mol