Question

Lake Chad is located centrally within the Sahel, a region south of the Sahara desert. The lake is very shallow; average depths vary between 1.5 and 5 m, with the result that the surface area of the lake changes so much from season to season that the lake is given two names: the "Gran Chad" has an area of 100 square kilometers, and the "Petit Chad" has an area of only 10 to 30 square kilometers.

The lake can be treated with stearic acid to slow evaporation rates. How many kg of stearic acid would be needed to ensure complete coverage of the lake with a monolayer of stearic acid, at a time when the lake's surface area is 94 km2?

We know that one stearic acid molecule covers 0.21 nm2, so by converting the lake's area into square nanometers, we can convert the area into molecules of stearic acid. The lake has an area of _______ m2, which is _______nm2. A stearic acid monolayer covering the entire lake will contain _________ molecules, which is ______ moles. Since stearic acid has a molar mass of 284.5 g/mol, the monolayer has a mass of _______ g, and ______. kg of stearic acid is needed to form the monolayer.

Answer 1