Consider the following equilibrium:
At equilibrium, 4.0 × 10-2mol H2, 4.0 × 10-2mol CO, 1.0 × 10-2mol H2O and 1.0 × 10-2mol C were present in a 1.0L container. What is the value of Keq?
a) 0.063
b) 16
c) 0.16
d) 6.3
I got b, but I'm not too certain about my answer.. Please help.
Keq can be obtained by substitution of the product concentrations and reactant concentrations in the definition of Keq.
If in doubt, read:
http://www.horton.ednet.ns.ca/staff/jeffrey/Chem%2012/answerkeysMJeffrey/kineticsandrates/Meaning%20of%20Keq%20page%201.pdf
or examples in
http://www.colgurchemistry.com/Chem12/Unit2Notes/Unit2Notesp62_82.pdf
To find the equilibrium constant, Keq, for this reaction, we need to use the concentrations of the reactants and products at equilibrium. Keq is calculated using the following expression:
Keq = [H2O]^1 * [C]^1 / [H2]^4 * [CO]^4
Given the concentrations in moles provided:
[H2] = 4.0 × 10^-2 mol / 1L = 4.0 × 10^-2 M
[CO] = 4.0 × 10^-2 mol / 1L = 4.0 × 10^-2 M
[H2O] = 1.0 × 10^-2 mol / 1L = 1.0 × 10^-2 M
[C] = 1.0 × 10^-2 mol / 1L = 1.0 × 10^-2 M
Now, substitute these values into the Keq expression:
Keq = (1.0 × 10^-2)^1 * (1.0 × 10^-2)^1 / (4.0 × 10^-2)^4 * (4.0 × 10^-2)^4
Simplifying:
Keq = (1.0 × 10^-2) / (4.0 × 10^-2)^4
Now evaluate this expression:
Keq = (1.0 × 10^-2) / (256 × 10^-8)
Keq = (1.0 × 10^-2) / (2.56 × 10^-6)
Keq = 3.90625
Comparing this answer to the given options, the closest choice is 4, so it seems that your initial answer of option b) 16 may be incorrect.
The correct option is d) 6.3, as it is the closest value to the calculated Keq.