Question

Lithium and nitrogen react to produce lithium nitride: `6Li(s) + N_2(g) -> 2Li_3N(s)`. How many moles of lithium nitride are produced when 0.710 mol of lithium react in this fashion?

Answer 1

We will obtain 0.237 mol of `Li_3N`

Explanation:

Since the given information is in moles, we need only look at the ratio between the chemicals:

Six moles of Li will produce 2 moles of lithium nitride. So, the ratio is 6:2 or 3:1.

Therefore, we can set up a proportion:

`(Li)/(Li_3N) = 3/1 = 0.710/x`

This tells us that in the general case, we need three times as much Li as the amount of `Li_3N` to be produced, and that the amount of `Li_3N` produced in this case must be in the same ratio. so, we can solve

`3/1 = 0.710/x`

Cross-multiply

`3x = 0.710`

`x= 0.710 -: 3 = 0.237` mol of `Li_3N` produced