Answer:
Explanation:
1) Chemical formula of sodium carbonate: <em>Na₂CO₃</em>
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.
Answer:
8.68 moles of BaI₂
Explanation:
Given data:
Number of moles of BaI₂ = ?
Number of formula units = 5.23× 10²⁴
Solution:
By using Avogadro number,
1 mole of any substance contain 6.022× 10²³ formula units.
5.23× 10²⁴ formula units of BaI₂ × 1 mol / 6.022× 10²³ formula units
0.868 × 10¹ moles of BaI₂
8.68 moles of BaI₂
Thus, 5.23× 10²⁴ formula units of BaI₂ contain 8.68 moles of BaI₂
"18) the element with the most stable nucleus and smallest mass per particle is:A) uranium.B)argon C) helium."