consider the reaction:
CO(aq) + Cl2 (aq) --> COCl2 (aq).
Calculate Delta G at non standard conditions. T = 298.15K. Concentration of COCl2 is reduced to 0.01832 M while the concentrations of CO and Cl2 remain 1M. Delta G rxn = -67.4 kj.
Even the correct formula to use would be a HUGE help!
Hey Tara,
Hmm, I'm not too sure about this question, but I'd guess it has something to do with the following formula:
G = G(not)+ RTlnQ
So basically G(not) = -67.4 kJ
R= 0.008314 kJ mol^-1 K^-1.(molar gas constant)(Note that units must be kJ to match up with the G(not) which is in kJ.)
Then.. T = 298.15K as you are given.
Then we need to calculate Q.
Being the reaction quotient, it is obtained by (concentration COCl2)/[(concentration CO)(concentration Cl2)] [In short, concentration of products/reactants]
You should get Q = (0.01832)/[(1)(1)]
Then just apply the formula.
If I'm not wrong, you should get -74.6kJmol^-1. :)
To calculate ΔG at non-standard conditions, we can use the equation:
ΔG = ΔG° + RT ln(Q)
Where:
ΔG = Gibbs free energy change at non-standard conditions
ΔG° = Gibbs free energy change at standard conditions (usually provided)
R = gas constant (8.314 J/(mol·K) or 0.008314 kJ/(mol·K))
T = temperature in Kelvin (298.15 K)
ln = natural logarithm
Q = reaction quotient
Given:
ΔG° = -67.4 kJ
T = 298.15 K
[COCl2] = 0.01832 M
[CO] = 1 M
[Cl2] = 1 M
To calculate Q, we need to use the concentrations of the reactants and products at non-standard conditions:
Q = [COCl2] / ([CO] * [Cl2])
Plug in the given values:
Q = 0.01832 / (1 * 1)
Q = 0.01832
Now we can calculate ΔG:
ΔG = ΔG° + RT ln(Q)
Note: We need to convert the value of ΔG° from kJ to J because the gas constant (R) is in J/(mol·K).
ΔG° = -67.4 kJ = -67,400 J
ΔG = -67,400 J + (0.008314 kJ/(mol·K) * 298.15 K * ln(0.01832))
ΔG = -67,400 J + (2.4848 kJ * ln(0.01832))
ΔG = -67,400 J + (2.4848 kJ * (-4.0000))
ΔG = -67,400 J - 9,939.52 J
ΔG = -77,339.52 J
Finally, convert the value of ΔG back to kJ:
ΔG = -77,339.52 J / 1000
ΔG ≈ -77.34 kJ
Therefore, ΔG at non-standard conditions is approximately -77.34 kJ.