# When the equation Li + O_2 -> Li_2O is correctly balanced, what is the sum ofthe coefficients?

May 10, 2017

$4 L i \left(s\right) + {O}_{2} \left(g\right) \rightarrow 2 L {i}_{2} O \left(s\right)$

#### Explanation:

The coefficients are selected so as to represent the conservation of mass. Is mass conserved in the given reaction? If it is not then it cannot be accepted as a representation of chemical reality. To make the arithmetic a bit easier we could write.........

$2 L i \left(s\right) + \frac{1}{2} {O}_{2} \rightarrow L {i}_{2} O \left(s\right)$

Interestingly, lithium metal is one of the few materials that will react with (otherwise inert!) dinitrogen gas to give lithium nitride, $L {i}_{3} N$.
$L i \left(s\right) + {N}_{2} \left(g\right) \rightarrow L {i}_{3} N \left(s\right)$.........