Consider the following equilibrium:
PCl3 + Cl2 = PCl5 Kc=26 @ 250 degree Celcius
1.0 mol of PCl3 , 1.0 mol of Cl2 , and 5.0 mol of PCl5 are placed in a 10.0L flask at 250 C and allowed to come to equilibrium. What is the concentration, in M, of at equilibrium?
Choose one answer.
a. 3.4
b. 0.19
c. 0.16
d. 0.13
e. 0.20
1. You didn't finish the problem What is the concn of ??????at equilibrium?
2. Note the correct spelling of celsius.
Kc = (PCl5)/(PCl3)(Cl2)
Convert moles to M. Set up an ICE chart and solve.
Consider the following equilibrium:
PCl3 + Cl2 = PCl5 Kc=26 @ 250 degree Celcius
1.0 mol of PCl3 , 1.0 mol of Cl2 , and 5.0 mol of PCl5 are placed in a 10.0L flask at 250 C and allowed to come to equilibrium. What is the concentration, in M, of Cl2 at equilibrium?
Choose one answer.
a. 3.4
b. 0.19
c. 0.16
d. 0.13
e. 0.20
I set up ICE:
PCl3 + Cl2 = PCl5
I 1.0/10.0 1/10.0 5/10.0
C -x -x +x
E 0.1-x 0.1-x 0.5+x
26= 0.5+x/(0.1-x)^2
so I then take the sqaure root of both sides to get rid of the ^2 then multiply 26(0.1-x)=0.5+x then take the square root of both sides
-0.5*5.099(0.1)=x2
but then I think I am confused in my math because I am thinking set up a quadratic equation formula for this problem?????Please Help
You have it going the wrong way. See my comments at your later post. Also, you can't solve by taking the square root of both side BECAUSE there is no squared term on top (just on the bottom). You must solve the quadratic equation.
To find the concentration of PCl3 at equilibrium, we can use the equilibrium constant (Kc) expression:
Kc = [PCl5] / ([PCl3] * [Cl2])
Let's substitute the given values into the equation:
Kc = 26 = [PCl5] / ([PCl3] * [Cl2])
We know that [PCl3] is 1.0 mol, [Cl2] is 1.0 mol, and [PCl5] is 5.0 mol. However, we need to convert these values to concentrations (M).
Concentration (M) = number of moles / volume (L)
For [PCl3]: [PCl3] = 1.0 mol / 10.0 L = 0.1 M
For [Cl2]: [Cl2] = 1.0 mol / 10.0 L = 0.1 M
And [PCl5]: [PCl5] = 5.0 mol / 10.0 L = 0.5 M
Now, let's substitute these values back into the equilibrium expression:
26 = (0.5 M) / ((0.1 M) * (0.1 M))
Simplifying the expression:
26 = 0.5 / 0.01
Now let's solve for [PCl3]:
[PCl3] = (0.5 / 26) * 0.01
Note: We are solving for the concentration of PCl3, so the answer will be in M (Molarity).
Calculating the answer:
[PCl3] = 0.01 * 0.5 / 26
[PCl3] ≈ 0.000192 M
Therefore, the concentration of PCl3 at equilibrium is approximately 0.000192 M.
The closest option to this value is 0.19 M, so the correct answer is (b) 0.19.