How much energy is required to decompose 765 g of PCl3, according to the reaction below? The molar mass of PCl3 is 137.32 g/mol and may be useful.
4 PCl3(g) → P4(s) + 6 Cl2(g), ΔH°rxn = +1207 kJ
1.68 × 10^3 kJ
To calculate the energy required to decompose 765 g of PCl3, we need to follow these steps:
Step 1: Calculate the number of moles of PCl3.
Given mass of PCl3 = 765 g
Molar mass of PCl3 = 137.32 g/mol
Number of moles = Mass / Molar mass
Number of moles = 765 g / 137.32 g/mol
Number of moles = 5.574 mol (approx)
Step 2: Use the stoichiometry of the balanced equation to determine the energy required.
According to the balanced equation:
4 PCl3(g) → P4(s) + 6 Cl2(g)
From the balanced equation, we can see that to produce 4 moles of PCl3, we need 1207 kJ of energy.
Step 3: Calculate the energy required to decompose 5.574 moles of PCl3.
Energy required = (Number of moles × Energy per mole)
Energy required = (5.574 mol × 1207 kJ / 4 mol)
Energy required = 1679.26 kJ (approx)
Therefore, approximately 1679.26 kJ of energy is required to decompose 765 g of PCl3 according to the given reaction.
To determine the energy required to decompose 765 g of PCl3, we need to use the given balanced equation and the molar mass of PCl3.
First, we need to convert the mass of PCl3 to moles. We can use the equation:
moles = mass / molar mass
Molar mass of PCl3 = 137.32 g/mol
moles of PCl3 = 765 g / 137.32 g/mol = 5.57 mol
Next, we can use the balanced equation and the stoichiometry to find the moles of Cl2 produced in the reaction. From the balanced equation, we can see that for every 4 moles of PCl3, 6 moles of Cl2 are produced.
moles of Cl2 = (moles of PCl3) x (6 moles of Cl2 / 4 moles of PCl3)
= 5.57 mol x (6/4)
= 8.36 mol
Now, we can use the equation's enthalpy change to determine the energy required for the reaction. The given enthalpy change (ΔH°rxn) is +1207 kJ.
Energy required = (ΔH°rxn) x (moles of Cl2)
= 1207 kJ x 8.36 mol
= 10,090.52 kJ
Therefore, the energy required to decompose 765 g of PCl3 is approximately 10,090.52 kJ.