A thin circular-disk earring 4.00 cm in diameter is plated with a coating of gold 0.25 mm thick from an Au³⁺ bath.(c) If the price of gold is $1595 per troy ounce (31.10 g), what is the total cost of the gold plating?

Respuesta :

Total Cost of Gold Plating is $621.58

Given

 diameter of circular-disk earring = 4.0 cm

 radius of circular-disk earring = 2.0 cm

  thickness of gold coating = 0.25 mm

   price of gold per troy ounce (31.10 g) =  $1595

 Now,

    We calculate the volume of gold that is coated on one side of circular-      disk earring  .

   hence,

            Volume = π r² × width

                           = 3.14 × (2cm)²× (0.25 mm ×[tex]\frac{1cm}{10mm}[/tex])

                           = 0.314 cm³

Now,

   Density of gold = 19.3 g/cm³

Now ,

      Mass of gold deposited on one side of earring is

 Mass = Density × Volume

         =  19.3 g/cm³ × 0.314 cm³

          = 6.06g

Similarly Mass of gold deposited on other side of earring is also 6.06g

Hence ,

    Total mass of gold deposited on earring = 6.06 × 2

                                                                         = 12.12g

Now given,

        Price of gold per troy ounce (31.10g) = $1595

        Price of 1 gram  of gold = [tex]\frac{1595}{31.10}[/tex] =51.286$/g

   Hence, Price of 12.12g gold = 51.286$/g ×12.12g

                Price of 12.12g gold = $621.586

Thus from above conclusion , we can say that the total cost of gold plating is $621.586

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