An aluminum foil 0.10 mm thick has how many aluminum atoms per square cm? (The density of aluminum is 2.7 × 10³ kg/ m³ and the atomic mass of aluminum is 27.)

Question

Quizplus · Accepted Answer

To find the number of atoms per square cm, first calculate the volume of aluminum in 1 cm² area with 0.10 mm thickness: 0.10 mm = 0.01 cm, so volume = 1 cm² × 0.01 cm = 0.01 cm³. Convert this to m³: 0.01 cm³ = 1 × 10⁻⁶ m³. The mass of this volume is density × volume = 2.7 × 10³ kg/m³ × 1 × 10⁻⁶ m³ = 2.7 × 10⁻³ kg. Convert mass to grams: 2.7 × 10⁻³ kg = 2.7 g. The number of moles is mass/atomic mass = 2.7 g / 27 g/mol = 0.1 mol. The number of atoms is moles × Avogadro's number = 0.1 mol × 6.022 × 10²³ atoms/mol = 6.022 × 10²² atoms. Therefore, the number of aluminum atoms per square cm is approximately 6 × 10²⁰.

An Aluminum Foil 0