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.
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Answer:</h2>
ZINC
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Explanation:</h2>
<em>To identify the element based on the informartion given, we have to find the molar mass since this mass is unique to each element.</em>
Molar mass = mass ÷ moles
<em>We already know the mass based on the question, as such we now need to find the # of moles.</em>
Since 1 mole contains 6.02214 × 10²³ atoms
then let x moles contain 4.19 × 10²³ atoms <em>(given in the question)</em>
<em> </em><em> </em> ⇒ x = (4.19 × 10²³ atoms × 1 mol) ÷ 6.02214 × 10²³ atoms
x = 0.69577 mol
<em>Now that we have the moles we can substitute it into the molar mass equation and solve for the molar mass.</em>
⇒ molar mass = 45.6 g ÷ 0.69577 mol
⇒ molar mass ≈ 65.54 g/mol
This molar mass is closest to that of ZINC.
Magnesium chloride is an example of an ionic compound which is a compound composed of ?
Magnesium chloride is a compound which is composed of positive and negative ions. I hope this helps you :)