Question

If a sample contains 100.0 g of lead atoms (Pb), how many atoms are present in the sample?

a. 100 atoms
b. 0.04826 atoms
c. 2.906 x 10^23 atoms
d. 3.441 x 10^ -24 atoms
e. 6.022 x 10^23 atoms

Answer 1

We have 2.906 * 10^23 lead atoms in the sample ( Option C is correct)

Step-by-step explanation:

Step 1: Data given

Mass of lead atoms = 100.0 grams

Number of Avogadro = 6.022 * 10^23 molecules / mol

Atomic mass of lead = 207.2 g/mol

Step 2: Calcumate moles lead atoms

Moles = mass / molar mass

Moles lead atoms = 100.0 grams / 207.2 g/mol

Moles lead atoms = 0.483 moles

Step 3: Calculate atoms

Number of atoms = number of moles * number of Avogadro

Number of moles = 0.483 moles * 6.022 * 10^23 atoms / mol

Number of moles = 2.906 * 10^23 atoms

We have 2.906 * 10^23 lead atoms in the sample ( Option C is correct)

Answer 2

The answer to your question is the letter C. 2.906 x 10²³ atoms

Step-by-step explanation:

Data

mass of Lead = 100 g

The Number of atoms = ?

Process

1.- Look for the atomic number of Lead in the periodic table

Atomic number = 207.2 g

2.- Use proportions and the Avogadro's number to calculate the number of atoms.

207.2 g ------------------ 6.023 x 10²³ atoms

100 g ----------------- x

x = (100 x 6.023 x 10²³) / 207.2

x = 6.025 x 10²⁵ / 207.2

x = 2.906 x 10²³ atoms