Nitrogen and hydrogen combine at high temperature, in the presence of a catalyst, to produce ammonia.

Question

N2(g)+3H2(g)-->2NH3(g)
Assume 4 molecules of nitrogen and 9 molecules of hydrogen are present.
After complete reaction, how many molecules of ammonia are produced?
How many molecules of H2 remain?
How many molecules of N2 remain?
What is the limiting reactant?

Answer 1

.........N2 + 3H2 ==> 2NH3
I........4......9.......0
C
E
If we take 4 N2 that will use up 3*4 = 12 molecules of H2 BUT we don't have 12 molecules; therefore, H2 must be the limiting reagent so in th table we will use H2
...........N2 + 3H2 ==> 2NH3
I..........4.....9.........0
C.........-3....-9........6
E..........1.....0........6

Answer 2

Molecules of H2: 3 molecules.

Nitrogen atoms present: 3 atoms

Moles of NH3 formed: 2 moles