To address this question, we need to understand the properties of 1 mol of sodium chloride (NaCl) and 1 mol of aluminum chloride (AlCl₃).
1. Molar Mass:
- The molar mass of sodium chloride (NaCl) is calculated by adding the atomic masses of sodium (Na) and chlorine (Cl). The atomic mass of sodium is approximately 22.99 g/mol and for chlorine, it is approximately 35.45 g/mol. Thus, the molar mass of NaCl is [tex]\( 22.99 + 35.45 = 58.44 \)[/tex] g/mol.
- The molar mass of aluminum chloride (AlCl₃) is calculated by adding the atomic masses of aluminum (Al) and chlorine (Cl). The atomic mass of aluminum is approximately 26.98 g/mol, and chlorine remains 35.45 g/mol. Since there are three chlorine atoms in the formula, the molar mass of AlCl₃ is [tex]\( 26.98 + (3 \times 35.45) = 26.98 + 106.35 = 133.33 \)[/tex] g/mol.
The molar masses are different, so this option is incorrect.
2. Number of Ions:
- 1 mol of NaCl dissociates into 1 mol of Na⁺ ions and 1 mol of Cl⁻ ions, totaling 2 mol of ions.
- 1 mol of AlCl₃ dissociates into 1 mol of Al³⁺ ions and 3 mol of Cl⁻ ions, totaling 4 mol of ions.
The number of ions differs, so this option is incorrect.
3. Number of Molecules:
- Sodium chloride (NaCl) and aluminum chloride (AlCl₃) are ionic compounds, not molecular compounds. Therefore, considering them in terms of molecules is incorrect.
4. Number of Formula Units:
- By the definition of Avogadro's number, 1 mol of any substance contains [tex]\( 6.02 \times 10^{23} \)[/tex] entities, whether they are atoms, molecules, or formula units.
As such, 1 mol of NaCl contains [tex]\( 6.02 \times 10^{23} \)[/tex] formula units, and 1 mol of AlCl₃ also contains [tex]\( 6.02 \times 10^{23} \)[/tex] formula units.
Considering all the points above, the best way to compare 1 mol of sodium chloride to 1 mol of aluminum chloride is:
Both are made up of [tex]\( 6.02 \times 10^{23} \)[/tex] formula units.
