In order to balance this equation you need to count each element and how many of the individual elements are in the equation. _H2+N2=2 NH3 You multiply the 2 (Which is the coefficient) by the 3 (which is the subscript) This would equal 6 which indicated there are 6 hydrogen atoms on the right side so the left side should also have 6 hydrogen atoms
The missing coefficient on the left side must multiple the 2 to become 6 hydrogen Answer=3