If 28 g of N_2N2 and 25 g of H_2H2 are reacted together, which one would be the limiting reactant?

1 Answer
May 22, 2017

N_2N2

Explanation:

If we assume here the product is ammonia, NH_3NH3, the equation looks like

N_2(g) + 3H_2(g) rightleftharpoons 2NH_3(g)N2(g)+3H2(g)2NH3(g)

To find the limiting reactant, let's convert the given masses of N_2N2 and H_2H2 to moles using their molar masses, and then divide the calculated number by the coefficient in front of it in the equation. Whichever number in the end is lower, that reactant is limiting.

Using the molar masses of N_2N2 and H_2H2:

28cancel(gN_2)((1molN_2)/(28.02cancel(gN_2))) = color(red)(1.0 mol N_2

25cancel(gH_2)((1molH_2)/(2.02cancel(gH_2))) = (12molH_2)/(3"(coefficient)") = color(blue)(4.0 mol H_2

Since N_2 is present in a lower relative amount than H_2, nitrogen is the limiting reactant.