A wafer with dimensions 12.00 cm * 12.00 cm * 0.0200 cm contains 0.239 moles of siliconHow many grams of Si does this represent?

Answer 1

Don't get tricked by the dimensions of the "wafer", this looks like simple conversion problem.

From the periodic table, we know that Si has a molar mass of 28.085 g/mol, we can use that to convert from moles to grams:

0.239 mol Si ( 28.085 g ) = 6.71 g of Si

( 1 mol Si )