Earth's oceans have an average depth of 3800 m, a total area of 3.63 108 km2, and an average concentration of dissolved gold of 5.8 10-9 g/L.
(a) How many grams of gold are in the oceans?
(b) How many cubic meters of gold are in the oceans?
Assuming the price of gold is $392.00/troy oz, what is the value of gold in the oceans (1 troy oz = 31.1 g; d of gold = 19.3 g/cm3)?
Copper can be drawn into thin wires. How many meters of 34-gauge wire (diameter = 6.304 10-3 in) can be produced from the copper in 5.09 lb of covellite, an ore of copper that is 66% copper by mass? (Hint: Treat the wire as a cylinder: V of cylinder = πr2h; d of copper = 8.95 g/cm3.)