Final answer:
To calculate the mass of phosphorus pentachloride produced from 2.74 g of chlorine gas, the molar mass of Cl2 is used, but additional information is required to complete the calculation.
Step-by-step explanation:
The question asks about the mass of phosphorus pentachloride (PCl5) that would be produced by the complete reaction of 2.74 g of chlorine gas (Cl2). To solve this, we first need to determine the amount in moles of chlorine gas, using the molar mass of Cl2 (2 x 35.45 g/mol). The balanced equation for the reaction between phosphorus (P) and chlorine gas to form phosphorus pentachloride is P4 + 10Cl2 → 4PCl5. From the molar ratios, we can see that 10 moles of Cl2 produce 4 moles of PCl5. Using stoichiometry and the input mass of Cl2, we can calculate the theoretical mass of PCl5 formed. Unfortunately, without additional information such as how much phosphorus is available, the exact mass cannot be calculated as the problem is incomplete.