Hi there
As a Chemistry student I've never understood this simple idea and that's why I'm asking anyone to help knock some sense into me. So my problem is NOT how to calculate moles, my problem is understanding the difference between the moles that you calculate in a reaction, given the mass of the reactant or product and obviously calculating the relative atomic/molecular mass, and the moles that's given in a balanced reaction. To make things a bit clearer, the calculated moles of a reaction is very small, small than zero in some cases followed by many other numbers before the first significant figure, but the moles presented in a balanced reaction are usually integers.
If anyone needs me to be more specific by all means ask and I will gladly provide an example as to what I'm stuck with.