Final answer:
To find the mass of PCl3 formed from the given reactants, we need to calculate the moles of P and Cl2 and identify the limiting reactant. Without additional information on reaction conditions or product distribution, we cannot determine the exact mass of PCl3 produced in the reaction.
Step-by-step explanation:
To calculate the mass of PCl3 formed from a mixture of 20.4 g of P and 79.2 g of Cl2, we first need to determine the limiting reactant. Phosphorus (P) and chlorine (Cl2) react to form phosphorus trichloride (PCl3) and phosphorus pentachloride (PCl5) according to the following equations:
- P + 3Cl2 → PCl3
- P + 5Cl2 → PCl5
We need to determine which reactant is the limiting reactant. We calculate moles of Cl2 using its molar mass (70.90 g/mol) and find that we have 79.2 g Cl2 / 70.90 g/mol Cl2 = 1.117 moles of Cl2. Phosphorus (P) has a molar mass of approximately 31.0 g/mol, so we have 20.4 g P / 31.0 g/mol P = 0.658 moles of P.
Comparing the mole ratios required for both reactions, it is not immediately clear which product will be favored without additional information, such as reaction conditions or further stoichiometric calculations based on the actual reactions and products. Therefore, based on the information provided, we cannot conclusively determine the mass of PCl3 formed.