Question

How many moles of sodium carbonate contain 1.773 × 1017 carbon atoms?

Answer 1

• 2.941 × 10⁻¹⁷ mol

Step-by-step explanation:

1) Chemical formula of sodium carbonate: Na₂CO₃

2) Ratio of carbon atoms:

• The number of atoms of C in the unit formula Na₂CO₃ is the subscript for the atom, which is 1 (since it is not written).

Hence, the ratio is 1 C atom / 1 Na₂CO₃ unit formula.

This is, there is 1 atom of carbon per each unit formula of sodium carbonate.

3) Calculate the number of moles in 1.773 × 10⁷ carbon atoms

• Divide by Avogadro's number: 6.022 × 10²³ atoms / mol

• number C moles = 1.773 × 10⁷ atoms / (6.022 × 10²³ atoms/mol)

• number C moles = 2.941 × 10⁻¹⁷ mol

Since, the ratio is 1: 1, the number of moles of sodium carbonate is the same number of moles of carbon atoms.