How many grams of argon (Ar) contain the same number of atoms as 27 g of aluminum (Al)?
A) 18 g
B) 27 g
C) 31 g
D) 40 g
E) 67 g

Question

Quizplus · Accepted Answer

The number of atoms in a sample is determined by its amount in moles. The molar mass of aluminum (Al) is approximately 27 g/mol, so 27 g of Al is 1 mole, containing Avogadro's number of atoms (approximately $6.022 \times 10^{23}$ atoms). Argon (Ar) has a molar mass of approximately 40 g/mol. Therefore, to have the same number of atoms as 1 mole of Al, you would need 1 mole of Ar, which is 40 g.

How Many Grams of Argon (Ar) Contain the Same Number