What are moles in chemistry?

It's the weight of avogadro num from atoms

First write a balanced chemical equation: 2K + Br2 - - - > 2KBR Find the limiting reactant by using the moles of each element and determining which one gives you the smallest number of moles of potassium bromide. 2.92 mol K (2 mol KBr/2 mol K) = 2.92 mol KBr 1.78 mol Br2 (2 mol KBR/1 mol Br2) = 3.56 mol KBr potassium is your limiting reactant so the max. number of moles of KBr that can be produced is 2.92 mol of KBr