Nickel coin has density 8.91 g/cm3. How much nickel is contained in a nickel coin that is 8.33% (by weight) of nickel? Recall that a nickel coin has a diameter of 21.21 mm and a thickness of 1.95 mm.

Question

Answer Choices :

511. g

2.04 g

73.7 g

0.511 g (Correct answer)

0.00644 g

Answer 1

First, we'll find the volume of the coin:

V = h π r²

V = volume in cm³ = ?

h = height = 1.95 mm x 1 cm / 10 mm = 0.195 cm

r = radius = 21.21 mm / 2 = 10.605 mm x 1 cm / 10 mm = 1.0605 cm

π = 3.1416

V = (0.195 cm)(1.0605 cm)² (3.1416) = 0.689 cm³

Next, we can find the mass of the coin, using the given density

0.689 cm³ x 8.91 g / cm³ = 6.139 g

Finally, we find the mass of the nickel

6.139 g x 8.33% = 0.511 g (3 sig. figs.)