Final answer:
Option C). The formula of a chloride of rhenium containing 63.6% rhenium is determined by calculating the mole ratio of rhenium to chlorine, which results in a 1:3 ratio corresponding to the chemical formula ReCl₃.
Step-by-step explanation:
The percentage composition of the constituent elements in the compound can be used to calculate the formula for this 63.6% rhenium compound. The ratio of rhenium to chlorine in compounds containing rhenium chloride can vary. Given the percentage of rhenium in the compound, we must compute the mole ratio of rhenium to chlorine in order to find the correct formula.
Assuming we have 100 g of the compound, we would have 63.6 g of rhenium and the remaining 36.4 g would be chlorine. Rhenium has a molar mass of approximately 186.2 g/mol, and chlorine has a molar mass of approximately 35.45 g/mol. Considering the masses, we can calculate the moles of each:
- Moles of Re = 63.6 g / 186.2 g/mol = 0.3415 mol
- Moles of Cl = 36.4 g / 35.45 g/mol = 1.0267 mol
Now by dividing both by the smaller number of moles, we find the simplest ratio between the two elements:
- Re:Cl = 0.3415 mol : 1.0267 mol
- Ratio ~ 1:3
Therefore, the formula that corresponds to a 1:3 ratio is ReCl₃., making the answer (c) ReCl₃..