Now put the values in the The degree of nesting is unlimited but all the brackets should be balanced. $$ = \frac {13.5}{27} = 0.5 Moles $$, Calculate the number of moles of magnesium oxide, MgO in The calculator will instantly calculate the results using the chemical equation for moles. Math and Technology have done their part, and now it's the time for us to get benefits. Disable your Adblocker and refresh your web page . Molecular Weight Calculator. You must multiply by 100 at the end to express the value as a percentage. (b) 0.25 moles of Iron, As per the periodic table, relative atomic mass of Iron (Fe) = 56 The molecular formula details the types of elemental atoms and the quantities of each type contained in a molecule of the compound. The molecular formula for water, for example, is H 2 O, showing that each water molecule is made of two atoms of the element hydrogen and one oxygen atom. To calculate moles, use the basic molar mass formula.