Question: how many moles of carbon atoms are there in 5g of carbon?
Answer: There are 6.02 x 1023 particles in a mole so 180 g of glucose must contain 6 x 6.02 x 1023 carbon atoms. This equals 3.61 x 1024 carbon atoms. So 5g glucose contains 2 x 1022 x 5 = 1023 carbon atoms.