Multiple Choice
How many moles are present in 82.5 grams of iron (Fe)? (Molar mass of Fe = 55.85 g/mol)
28
views
2. Atoms & Elements
Mole Concept
Struggling with General Chemistry?
Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
Which statement best compares 1 mol of sodium chloride (NaCl) to 1 mol of aluminum chloride (AlCl_3)?
A
Both contain the same number of formula units.
B
1 mol of NaCl contains more atoms than 1 mol of AlCl_3.
C
1 mol of NaCl contains more formula units than 1 mol of AlCl_3.
D
1 mol of AlCl_3 contains more formula units than 1 mol of NaCl.
Verified step by step guidance1
Recall that 1 mole of any substance contains Avogadro's number of formula units, which is approximately \$6.022 \times 10^{23}$ units.
Understand that a formula unit refers to the simplest ratio of ions represented in an ionic compound, so 1 mole of NaCl contains \$6.022 \times 10^{23}\( formula units of NaCl, and 1 mole of AlCl\)_3\( contains \)6.022 \times 10^{23}\( formula units of AlCl\)_3$.
Compare the number of atoms in each mole by considering the composition of each formula unit: NaCl has 1 Na atom and 1 Cl atom (total 2 atoms per formula unit), while AlCl\(_3\) has 1 Al atom and 3 Cl atoms (total 4 atoms per formula unit).
Calculate the total number of atoms in 1 mole of each compound by multiplying the number of atoms per formula unit by Avogadro's number, which shows that 1 mole of NaCl contains fewer atoms than 1 mole of AlCl\(_3\).
Conclude that both 1 mole of NaCl and 1 mole of AlCl\(_3\) contain the same number of formula units, but differ in the total number of atoms due to their different compositions.
Related Videos
Related Practice
