How many atoms are in a drop of mercury that has a diameter of 1.0 mm? (Volume of a sphere is 4 $\pi$r³/3; density of mercury = 13.6 g/cm³) A) 2.1 * 10¹⁹ B) 1.7 *10²⁰ C) 2.1 *10²² D) 1.7 * 10²³ E) None of these choices is correct.

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Quizplus · Accepted Answer

The volume of the drop is:$$V = \frac{4}{3}\pi r^3 = \frac{4}{3}\pi (0.5 	ext{ mm})^3 = 0.524 	ext{ mm}^3$$The mass of the drop is:$$m = ho V = (13.6 	ext{ g/cm}^3)(0.524 	ext{ mm}^3) = 7.12 	ext{ mg}$$The number of atoms in the drop is:$$N = \frac{m}{M}N_A = \frac{(7.12 	ext{ mg})(10^{-3} 	ext{ g/mg})}{200.59 	ext{ g/mol}}(6.022 	imes 10^{23} 	ext{ atoms/mol}) = 2.1 	imes 10^{19} 	ext{ atoms}$$

How Many Atoms Are in a Drop of Mercury That π\piπ

How Many Atoms Are in a Drop of Mercury That $\pi$