Question

for the reaction, calculate how many moles of the product form when 0.036mol of O2 completely reacts. 2Ca+O2->2 CaO

Answer 1

Since your equation is balanced, you can jump straight to using the molar ratio. 0.036 mol O2*(2 mol CaO/1 mol O2) = 0.072 mol CaO. I put moles of O2 in the denominator so that unit would cancel.