Phosphorus pentachloride reacts to form phosphorus trichloride and chlorine gas when heated. A 2.00 liter vessel contains 0.020 moles of phosphorus trichloride and chlorine at equilibrium. How many moles of phosphorus pentachloride are present? Kc=0.0415
Here is step by step for nearly all these prolbems. Go thru the rest, and we can critique for you.
a. Write the balancee equation:
PCl5 <<>> PCl3 + Cl2
b. Write the equilibrium expression:
k= [PCl5][Cl2]/[PCl5]
because moles/volume=concentration, and volume is 2 liters, then
0.0415=.01*.01/x
solve for x, the concentration of PCl5
moles present? x*volume for moles=2*x
To solve this problem, we can use the equilibrium constant expression and the given information to determine the number of moles of phosphorus pentachloride present.
The balanced chemical equation for the reaction is:
PCl₅ (g) ⇌ PCl₃ (g) + Cl₂ (g)
The equilibrium constant expression, Kc, is given as:
Kc = [PCl₃] * [Cl₂] / [PCl₅]
We are given that the equilibrium concentration of phosphorus trichloride ([PCl₃]) and chlorine gas ([Cl₂]) in the 2.00 liter vessel is both 0.020 moles.
Let x be the number of moles of phosphorus pentachloride ([PCl₅]) at equilibrium.
Therefore, the equilibrium concentration of phosphorus trichloride ([PCl₃]) and chlorine gas ([Cl₂]) can be expressed as:
[PCl₃] = 0.020 moles
[Cl₂] = 0.020 moles
Plugging these values into the equilibrium constant expression, we have:
0.0415 = (0.020) * (0.020) / x
Simplifying the equation:
0.0415 = 0.0004 / x
To isolate x, we can rearrange the equation:
x = 0.0004 / 0.0415
Evaluating this expression gives:
x ≈ 0.009638 moles
Therefore, there are approximately 0.009638 moles of phosphorus pentachloride present in the 2.00 liter vessel at equilibrium.