Final answer:
The calculation of moles from mass for mercury and chlorine involves dividing the given masses by their respective atomic or molar masses. The moles of each element are then used to determine the empirical formula of mercury chloride by establishing a simple whole number ratio.
Step-by-step explanation:
To find out how many moles of mercury and chlorine are represented by the individual masses given in the solution containing 74.748g of mercury(II) chlorate, we use the molar masses of the elements. For mercury (Hg), which has an atomic mass of approximately 200.59 g/mol, and for chlorine (Cl), which has an atomic mass of approximately 35.45 g/mol per atom (but note that in chlorate, Cl is part of a polyatomic ion along with oxygen).
Example: If the compound is 73.9% mercury by mass, a 100 gram sample would contain 73.9 grams of mercury. The number of moles of mercury would therefore be 73.9 g / 200.59 g/mol, which is approximately 0.368 moles of Hg. Similarly, for chlorine in the chlorate, we would use the chlorine part of the molar mass of the chlorate ion, considering the percentage by mass and the total molar mass of the compound.
However, the question is incomplete; we would require the molar mass of mercury chlorate to accurately determine the moles of chlorine in the sample.
For the empirical formula of a compound that is 73.9% mercury and 26.1% chlorine by mass, you'd calculate the moles of each element and then divide by the smallest number of moles to get the simplest whole number ratio. For mercury chloride, assuming the sample is 100 grams, the moles of mercury would be calculated as before, and chlorine moles would be similarly calculated using its percentage mass and atomic mass.