Why are figures removed from the calculation for values that are known in more detail? E.g. if you want to calculate the number of moles in 75.0 g H2 molecules. Why should one here use
for the relative atomic mass/molar mass of H 1,008 u or g/mol instead of 1,0079 u or g/mol?
What is the purpose of this?
In addition to that, should one round interim results like the substance amount, the molar mass or should one just round the final result?