What amount moles is represented by each of these samples? a.150.0 g Fe2 o3 b.10.0 mg NO2 C 1.5 *10 ^16 molecules of BF3?

pisgahchemist

How many moles ..... 150.0g Fe2O3 x (1 mol Fe2O3 / 159.6g Fe2O3) = 0.9398 mol Fe2O3 10.0 mg NO2 x (1g / 1000 mg) x (1 mol NO2 / 46.0g NO2) = 2.17x10^-4 mol NO2 1.5x10^16 molecules BF3 x (1 mol BF3 / 6.022x10^23 molecules BF3) = 2.5x10^-8 mol BF3 Note the precision of the answers. Four significant digits for A, but only two significant digits are allowed for C.