Issued as a cumulative or non-cumulative L/C, the former allows for unused credit amounts to rollover into subsequent periods while the latter maintains a fixed amount of credit available each period.
average atomic mass of magnesium is 24.3 g/mole so 24.3 X 1.56 X1021 / 6.02 X1023 = .063 grams.
The molar mass equals the sum of the atomic. masses expressed in g/mol. (b) The sum of the atomic masses for NH. 3 is 14.01 amu + 3(1.01)amu = 17.04 amu. The molar mass of ammonia equals 17.04 g/mol. The molar mass of magnesium nitrate equals 148.33 g/mol.