* Avogadro's Number: One mole of any substance contains 6.022 x 10^23 particles (atoms, molecules, etc.). This is known as Avogadro's number.

* Calculation:

* 0.75 moles of carbon atoms * (6.022 x 10^23 atoms/mole) = 4.5165 x 10^23 carbon atoms

Therefore, there are approximately 4.5165 x 10^23 carbon atoms in 0.75 moles of carbon atoms.