How many atoms of carbon are needed to produce 0.45 mol Al?

Question

3C + 2Al2O3 4Al + 3CO2

A. 2.6 × 1026 atoms
B. 9.7 × 1024 atoms
C. 3.0 × 1022 atoms
D. 2.0 × 1023 atoms

Answer 1

Use the coefficients in the the balanced equation.
mols C needed = 0.45 mol Al x (3 mols C/4 mols Al) = ?
Then you know that 1 mol C contains 6.02E23 atoms.