Consider the hypothetical reaction A + 3B → 2C. If 6.5 moles of reactant A is combined, how many moles of C can be formed?

Answer 1

While @Kevin E.'s answer is quite correct, I thought it might help the OP if this were shown using dimensional analysis, as follows:

6.5 moles A x 2 moles C/1 mole A = 13 moles C

(Note that moles of A cancel leaving you with moles of C as desired)