Question

A balanced equation tells you the mole ratio of all reactants and products. Using the chemical reaction below how many moles of NH3 are made when 3 moles of hydrogen gas are used?
2N2 + 3H2 ---> 2NH3

Answer 1

From  the  reaction  above    2  moles  of  N2  reacted  with  3  moles  of  H2  to  give  2  moles of   ammonia
THese  implies  that   the   mole  ratio  of  hydrogen  to  ammonia   is   3:2
Therefore  if   3  moles  of  hydrogen   were  used  the  moles  of  ammonia  is  therefore
(3 x2)/3=  2moles

Answer 2

By using the mole ratio, we can determine that 2 moles of NH3 are made when 3 moles of hydrogen gas are present. The numbers in front of the chemicals tell us the relative amounts consumed and produced. Since there is a 3 in front of H2 and a 2 in front of NH3, this tells us that for every 3 moles of H2 gas used, 2 moles of NH3 are made.