Question

Calculate the cost of a single aluminum atom in a roll of aluminum foil, correct to 3 significant digits.

- The cost of a roll is $2.39

- The area of the roll is 9.28 square meters

- Given an 8"x8" section

Answer 1

Given that area of the roll = 9.28 m²

So, cost per area = $2.39 / 9.28 m²

Given that 8"x8" section = 8"x8" = 64 in² = 64 x (0.254 m)²       [ 1 inch = 0.0254 m]

            = 0.041 m²

Hence,

cost of a single aluminum atom = ($2.39 / 9.28 m²) x 0.041 m² x (1/avagadro number)

                                              = ($2.39 / 9.28 m²) x 0.041 m² x (1/6.022 x 10²³ atoms)

                                              = $ 0.0017 x 10^-23