Question #e8833

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Answer 1 · 2015-01-17T19:56:01

The answer is $4.67 * 10^(24)$ $"atoms"$ .

So, start by converting inches to cm

$"0.929 cm" * ("2.54 cm")/("1 inch") = "2.360 cm"$

Use this value to determine the volume of the sphere

$V_("sphere") = 4/3 * pi * r^3 = 4/3 * 3.14 * 2.360^3 = 55.03$ $"cm"^3$

Use density to determine the mass of copper

$rho = m/V => m = rho * V = 8.96$ $"g"/"cm"^3 * 55.03$ $"cm"^3 = 493$ $"g"$

From here, you can determine the number of atoms you have by

$"493 g" * (6.022 * 10^23 "atoms")/("63.55 g") = 4.67 * 10^24$ $"atoms"$

I've used the fact that 1 mole of copper has $6.022 * 10^23$ atoms and weighs $"63.55 g"$ .