A piece of pencil graphite (made of carbon atoms) has a mass of 0.12 grams. How many moles of carbon atoms are in the lead?

Moles = 0.01 mol

Number of Atoms = 6.022 * 10²¹ Atoms

Solution:

Data Given:

Mass = 0.12 g

M. Mass of Carbon = 12.01 g. mol⁻¹

Calculating Moles:

As we know,

Moles = Mass : M. Mass

Putting values,

Moles = 0.12 g : 12.01 g. mol⁻¹

Moles = 0.01 mol

Calculate Number of Atoms as,

Moles = Number of Atoms : 6.022 * 10²³ Atoms. mol⁻¹

Solving for Number of Atoms,

Number of Atoms = Moles * 6.022 * 10²³ Atoms. mol⁻¹

Putting value of Moles,

Number of Atoms = 0.01 mol * 6.022 * 10²³ Atoms. mol⁻¹

Number of Atoms = 6.022 * 10²¹ Atoms