Final answer:
The theoretical yield of lithium nitride when 12.1 g of lithium is reacted with 33.0 g of nitrogen is 20.25 g, and the percent yield of the reaction, given an actual yield of 5.01 g, is 24.74%.
Step-by-step explanation:
When lithium is heated with nitrogen, they combine to form lithium nitride(Li₃N), an important component in advanced batteries. To determine the theoretical yield of Li₃N, we first need to carry out a stoichiometry calculation using the balanced equation:
6Li(s) + N₂(g) → 2Li₃N(s)
We start by calculating the molar mass of Li (6.94 g/mol) and N₂(28.02 g/mol). Then we convert the masses of Li and N₂ to moles:
Using the stoichiometry of the reaction, we can see that 6 moles of Li react with 1 mole of N₂. Therefore, the lithium is the limiting reactant in this reaction. For every 6 moles of Li, 2 moles of Li₃N are produced:
The molar mass of Li₃N is (3×6.94) + 14.01 = 34.83 g/mol, so we can calculate the theoretical yield:
The theoretical yield of Li₃N is, therefore, 20.25 g.
To calculate the percent yield, we use the actual yield and theoretical yield:
The percent yield of the reaction is 24.74 %.