The mass of a mole of carbon atoms is 12.011 grams. What is the mass of a single atom of carbon?

Amount of substance can be measured in the number of moles.

Avagadros constant states that 1 mol of any substance is made of 6.022 x 10^23 units.

These units could be atoms making up elements or molecules making up compounds

1 mol of C is made of 6.022 x 10^23 atoms of C

Since 1 mol of C has a mass of 12.011 g

Therefore 6.022 x 10^23 atoms of C weigh 12.011 g

Then 1 atom of C weighs - 12.011 g / 6.022 x 10^23 atoms = 1.99 x 10^ (-23) g

Mass of 1 C atom is 1.99 x 10^ (-23) g