39.3 grams of sulfur reacted completely with 246 grams of mercury to form HgS.
<u>FURTHER EXPLANATION</u>
To solve this problem, first write the balanced chemical equation for the given reaction:
Hg + S → HgS
To solve the problem, we use the stoichiometric ratios of mercury and sulfur.
First, convert the mass of mercury to moles using the molar mass (200.59 g/mol).

Now, determine the moles of sulfur formed using the stoichiometric ratio of sulfur and mercury which is 1:1

To get the mass of sulfur that reacted with mercury to form HgS, use the molar mass of sulfur (32.06 g/mol)

Since the given only has 3 significant figures, the final answer must also have the same. Therefore,

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<em>Keywords: stoichiometry, dimensional analysis</em>