Answer:
142.36 kg
Explanation:
volume of water in the lake = surface area x depth
= 18.5 x ( 1760 x 3 )² x 39 ft³
= 2.011 x 10¹⁰ ft³
= 2.011 x 10¹⁰ x 28.3168 liter .
= 56.945 x 10¹⁰ liter .
concentration of mercury = .25 x 10⁻⁶ g / liter
= 25 x 10⁻⁸ g / liter
= 25 x 10⁻¹¹ kg / liter
mass of mercury in the water of lake
= 25 x 10⁻¹¹ x 56.945 x 10¹⁰ kg
= 142.36 kg .