What mass of aluminum contains the same number of atoms as 3.0 g of lead?
A) 23 g
B) 0.014 g
C) 3.0 g
D) 0.39 g
E) 0.11 g

Question

Quizplus · Accepted Answer

We need to use Avogadro's number to find the number of atoms in 3.0 g of lead.

Number of atoms in 3.0 g of lead (Pb):
= (3.0 g) / (207.2 g/mol) * (6.022 x 10^23 atoms/mol)
= 8.67 x 10^21 atoms

Now we need to find the mass of aluminum that contains the same number of atoms. Since aluminum has a smaller atomic mass than lead, we need a larger mass of aluminum to contain the same number of atoms.

Let x be the mass of aluminum in grams:
( x g / 26.98 g/mol) * (6.022 x 10^23 atoms/mol) = 8.67 x 10^21 atoms

Solving for x gives:
x = 0.39 g

Therefore, the mass of aluminum that contains the same number of atoms as 3.0 g of lead is 0.39 g, which is choice D.

What Mass of Aluminum Contains the Same Number of Atoms