How do you balance Al + N_2 -> AlN?

1 Answer
Jan 27, 2016

Use a non-integral coefficient.

Explanation:

$A l \left(s\right) + \frac{1}{2} {N}_{2} \left(g\right) \rightarrow A l N \left(s\right)$

Is this equation balanced? How do you know? Of course, your teacher might want you to use integral coefficients. The point is that while I cannot have half a molecule of dinitrogen, I can certainly have 14 g dinitrogen, i.e. half a mole. The stoichiometry will be the same in either case.

Could I multiply each side of the equation by 2? Would this change the stoichiometry? Note that the use of 1/2 coefficients has long precedent when solving stoichiometric problems.