Relative Atomic Mass (RAM) is the mass of an elements atom relative to carbon-12.
The Mr of a substance is the sum of the relative atomic masses. \[\textup{mol}=\frac{\textup{mass}}{\textup{M\textsubscript{r}}}\]
The number of atoms in a mole of any given substance is fixed: \(6.02\times10^{23}\)
The percentage yield of a reaction can be reduced by:
Loss of products from reaction vessel
Side-reactions to give unwanted products
Impurities in reactants
Changes in conditions
The reaction being an equilibrium system
\[\textup{Percentage Yield}=\frac{\textup{actual yield}}{\textup{theoretical yield}}\times100\]