Phosphorous trichloride (PCl3) is produced
from the reaction of white phosphorous (P4)
and chlorine:
P4(s) + 6Cl2(g) ! 4 PCl3(g) .
A sample of PCl3 ofmass 280.7 g was collected
from the reaction of 70.86 g of P4 with excess
chlorine. What is the percentage yield of the
reaction?
Answer in units of %.
Well, it looks like we have a reaction that has gone from being a complete "Clown Show" to a stoichiometry question. Let's calculate that percentage yield!
To begin with, we need to determine the theoretical yield, which is the maximum amount of product that can be formed based on the balanced equation. The molar mass of PCl3 is 137.33 g/mol, so we can calculate the theoretical yield like this:
70.86 g P4 * (4 mol PCl3 / 1 mol P4) * (137.33 g PCl3 / 1 mol PCl3) = 390.8 g PCl3 (approximately)
Now, we can calculate the percentage yield using the formula:
Percentage Yield = (Actual Yield / Theoretical Yield) * 100
Plugging in the values:
Percentage Yield = (280.7 g / 390.8 g) * 100 = 71.8%
So, the percentage yield of the reaction is approximately 71.8%. And just like that, chemistry becomes a laughing matter!
To find the percentage yield of the reaction, you need to calculate the theoretical yield and then divide the actual yield by the theoretical yield, multiplying by 100 to get the result as a percentage.
First, calculate the theoretical yield:
1. Determine the molar mass of P4:
P = 1 * 4 = 4 g/mol
P4 = 4 g/mol
2. Calculate the number of moles of P4:
Moles of P4 = mass of P4 / molar mass of P4
Moles of P4 = 70.86 g / 123.895 g/mol = 0.571 mol
3. Determine the molar ratio between P4 and PCl3:
According to the balanced chemical equation, 1 mol of P4 produces 4 mol of PCl3.
4. Calculate the moles of PCl3 produced:
Moles of PCl3 = moles of P4 * (4 mol PCl3 / 1 mol P4)
Moles of PCl3 = 0.571 mol * (4 mol PCl3 / 1 mol P4) = 2.284 mol
5. Calculate the mass of PCl3 produced:
Mass of PCl3 = moles of PCl3 * molar mass of PCl3
Mass of PCl3 = 2.284 mol * 208.24 g/mol = 475.4 g
Now, calculate the percentage yield:
1. Actual yield = 280.7 g (given in the question)
2. Percentage yield = (Actual yield / Theoretical yield) * 100
Percentage yield = (280.7 g / 475.4 g) * 100
Percentage yield ≈ 59.03%
Therefore, the percentage yield of the reaction is approximately 59.03%.
To calculate the percentage yield of a reaction, you need to know the actual yield and the theoretical yield.
Theoretical yield refers to the amount of product that would be obtained if the reaction proceeded perfectly, with all reactants being converted to the desired product. It is calculated based on the stoichiometry of the balanced chemical equation.
In this case, the balanced equation is:
P4(s) + 6Cl2(g) → 4PCl3(g)
From the equation, you can determine the molar ratio between P4 and PCl3. For every 1 mole of P4, you get 4 moles of PCl3.
Given that 70.86 g of P4 was used, you can convert this mass to moles using the molar mass of P4. The molar mass of P4 is 123.89 g/mol (4P × atomic mass of P = 4 × 30.97 g/mol = 123.89 g/mol).
Moles of P4 = Mass of P4 / Molar mass of P4
Moles of P4 = 70.86 g / 123.89 g/mol
Moles of P4 ≈ 0.571 mol
Using the ratio from the balanced equation, you can now calculate the theoretical yield of PCl3:
Theoretical yield of PCl3 = Moles of P4 × (4 moles of PCl3 / 1 mole of P4)
Theoretical yield of PCl3 = 0.571 mol × (4/1)
Theoretical yield of PCl3 = 2.284 mol
Now, the actual yield is given as 280.7 g. To calculate the percentage yield, divide the actual yield by the theoretical yield and multiply by 100:
Percentage yield = (Actual yield / Theoretical yield) × 100
Percentage yield = (280.7 g / (2.284 mol × (30.97 g/mol))
Percentage yield ≈ 100%
Therefore, the percentage yield of the reaction is approximately 100%.