At a certain temperature, the equilibrium constant, Kc, for this reaction is 53.3.
H2(g)+I2(g) <-> 2HI(g)
At this temperature, 0.300 mol of H2 and 0.300 mol of I2 were placed in a 1.00-L container to react. What concentration of HI is present at equilibrium?
Have you ever used an ICE table?
Here is a great tutorial, but it takes some paying attention.
http://chemwiki.ucdavis.edu/Physical_Chemistry/Chemical_Equilibrium/Le_Chatelier%27s_Principle/Ice_Tables
yes i have used an ICE table that is what we are learning right now but this one is giving me problems, i keep getting the wrong answer and i don't know why
To find the concentration of HI at equilibrium, we need to use the equilibrium constant expression and calculate the concentrations of reactants and products.
The equilibrium constant expression for this reaction is:
Kc = [HI]^2 / ([H2] * [I2])
Given:
[H2] = 0.300 mol
[I2] = 0.300 mol
Kc = 53.3
To find the concentration of HI, we need to assume that x is the change in concentration of HI at equilibrium. Since 2 mol of HI is formed for every 1 mol of H2 and I2 reacted, the concentrations of H2 and I2 will decrease by 0.300 mol * x.
So, the equilibrium concentrations can be expressed as follows:
[H2] = (0.300 - 0.300 * x) mol
[I2] = (0.300 - 0.300 * x) mol
[HI] = 2x mol
Now we can substitute these values into the equilibrium constant expression:
Kc = [HI]^2 / ([H2] * [I2])
53.3 = (2x)^2 / ((0.300 - 0.300 * x) * (0.300 - 0.300 * x))
Simplifying and rearranging the equation:
53.3 = 4x^2 / (0.09 - 0.18x + 0.09x^2)
Solving for x requires solving a quadratic equation. We can rearrange the equation to:
2.09x^2 - 9x + 1.77 = 0
Now we can use the quadratic formula to solve for x:
x = (-b ± √(b^2 - 4ac)) / 2a
In this case, a = 2.09, b = -9, and c = 1.77. Plugging these values into the quadratic formula gives us two possible values for x. Let's assume x1 and x2 are the root values obtained from the quadratic formula.
After obtaining x1 and x2, we need to check if these values of x are valid concentrations at equilibrium. We can do this by checking if the concentrations of H2 and I2 are non-negative when substituted into the equilibrium concentrations expression:
0.300 - 0.300 * x ≥ 0
0.300 - 0.300 * x ≥ 0
If both inequalities are satisfied, we can proceed to calculate [HI] at equilibrium using the equation:
[HI] = 2x
Evaluate [HI] at equilibrium using the valid value of x.