Answer:
a) Limiting: sulfur. Excess: aluminium.
b) 1.56g Al₂S₃.
c) 0.72g Al
Explanation:
Hello,
In this case, the initial mass of both aluminium and sulfur are missing, therefore, one could assume they are 1.00 g for each one. Thus, by considering the undergoing chemical reaction turns out:

a) Thus, considering the assumed mass (which could be changed based on the one you are given), the limiting reagent is identified as shown below:

Thereby, since there 1.00g of aluminium will consume 0.0554 mol of sulfur but there are just 0.0156 mol available, the limiting reagent is sulfur and the excess reagent is aluminium.
b) By stoichiometry, the produced grams of aluminium sulfide are:

c) The leftover is computed as follows:

NOTE: Remember I assumed the quantities, they could change based on those you are given, so the results might be different, but the procedure is quite the same.
Best regards.
<em>Question: </em><em>Which cup has more thermal energy?</em>
<em> A. 2 liter cup of milk</em>
<em> B. 1 liter cup of milk</em>
<em>Answer: A. 2 liter cup of milk</em>
<em />
<em>Explanation:</em>
We have milk in both of the containers. The milk in both containers is the same temperature, so we will have to measure the amount of molecules. The amount of molecules makes it warmer, and if it is warmer, that is more energy. 2 liters have more thermal energy than 1 liter, because it has more molecules.
Our answer is 2 liter cup of milk.