Final answer:
To determine the moles of Li2S produced from 142.69 g of LiOH, one must calculate the number of moles of LiOH based on its molar mass and then apply the stoichiometric ratio from the balanced equation to find the amount of Li2S generated.
Step-by-step explanation:
The question involves determining the number of moles of Li2S produced from a given mass of LiOH when it reacts with excess H2S. This is a classic stoichiometry problem. The balanced chemical equation given is:
2 LiOH + H2S → Li2S + 2 H2O
To find the moles of Li2S produced, we first need to calculate the moles of LiOH using its molar mass. Then, we apply the mole ratio from the balanced equation to determine the moles of Li2S.
First, calculate the moles of LiOH:
moles LiOH = mass LiOH / molar mass LiOH
Next, use the stoichiometry from the balanced equation to find the moles of Li2S produced:
moles Li2S = (moles LiOH) × (1 mol Li2S/2 mol LiOH)
Finally, use the result to report the number of moles of Li2S produced.