a. One thousand tonnes (1000t, t=10^3 kg) of sand contains about a trillion grains of sand. How many tonnes of sand are needed to provide 1 mol of grains of sand?
b. Presuming the volume of a grain of sand is 1 mm^3 and the land area of the continental U.S. is 3.6*10^6 mi^2, how deep would the sand pile over the U.S. be of this area were evenly covered with 1 mol of grains of sand?