There are 252.07 grams of ammonium dichromate per mol of ammonium dichromate molecules. There are 8 atoms of hydrogen per molecule of ammonium dichromate.
Convert grams to mole of molecules. And then molecules to atoms.
55.90 / 252.07 = moles of molecules
Since there are 8 hydrogen per 1 molecule multiply this by 8.
To calculate the molar mass of a compound, you multiply the subscripts of each element times its molar mass (atomic weight in g/mol). (NH 4 ) 2 Cr 2 O 7 When there is no written subscript, it is understood to be 1 . Also, when elements are enclosed in parentheses, the subscripts on the inside are multiplied by the number outside the parentheses. Molar Masses of the Elements Nitogen: 14.007 g/mol