Here's how to calculate the number of atoms in 3.5 moles of carbon:

1. Avogadro's Number

* Avogadro's number tells us the number of particles (atoms, molecules, etc.) in one mole of a substance. It's approximately 6.022 x 10^23 particles/mol.

2. Calculation

* Step 1: Multiply the number of moles by Avogadro's number:

3.5 mol * (6.022 x 10^23 atoms/mol) = 2.1077 x 10^24 atoms

Answer: There are approximately 2.1077 x 10^24 atoms in 3.5 moles of carbon.