When the oxide of generic metal M is heated at 25.0 °C, only a negligible amount of M is produced.

O2M(s) ----> M(s) +O2(g) delta G= 288.9 Kj/mol

When this reaction is coupled to the conversion of graphite to carbon dioxide, it becomes spontaneous. What is the chemical equation of this coupled process? Show that the reaction is in equilibrium, include physical states, and represent graphite as C(s).

I got an answer of :

O2M(s)+ C(s) ----> M(s) + CO2(g)

This is correct. I need help on this part of the question:
What is the thermodynamic equilbrium constant for the coupled reaction?
I attempted this twice and got
K=1.22 and 0.89 and they are both wrong. Please help.

User Icon for DrBob222 DrBob222 answered
12 years ago

I would add 288.9 to dGof for CO2 of -394.4 for -105.5 kJ/mol for the reaction you show. Then

(105,500/8.314*298) = lnK and i get a huge number for K. Somethng like 3.1E18
Check that carefully.

User Icon for Jerry Jerry answered
12 years ago

yes it is correct! Thanks so much! You are the best!!!!!

User Icon for Coolguy Coolguy answered
11 years ago

K=e raised to -(-106.4 kj/mol)/(8.314e-3kj/mol*298k)

K=4.476e18 is what I got.

User Icon for Andrew Andrew answered
11 years ago

I keep getting the equation wrong!

User Icon for J J answered
10 years ago

my deltaGf was dGf=290.4kJ/mol

i got K=1.69e18 as my answer and it was correct.
still getting the equation wrong though :/

User Icon for Janavi Janavi answered
10 years ago

1: Set all the delta g's for solids equal to 0

2:Find thr delta g for the gases.
3:Find the delta g for the second equation.
4:Add the delta g's for the 2 questions together.
5: Solve for the value of Q using the equation
-Delta G not =RTLnQ

User Icon for HitGirl HitGirl answered
10 years ago

COMBINE THE 2 EQUATIONS TOGETHER PEOPLE!

MO2 + C <-> CO2 + M

User Icon for Chris Chris answered
9 years ago

Original deltaG=288.9

deltaG(system)=deltaG[CO2]+deltaG[M]-deltaG[MO2]-deltaG[C]

look up deltaG value from table for CO2=-394.4

DeltaG for a solid is almost always zero (C)

So -394.4+288.9=deltaGsystem

then

K=e^((deltaGsystem)/((8.314/1000)*298)))

User Icon for sdtfer sdtfer answered
7 years ago

ert5y547

User Icon for Explain Bot Explain Bot answered
11 months ago

To determine the thermodynamic equilibrium constant for the coupled reaction, you need to use the relationship between the standard Gibbs free energy change (ΔG°) and the equilibrium constant (K).

The standard Gibbs free energy change (ΔG°) is related to the equilibrium constant (K) by the equation:

ΔG° = -RTln(K)

Where:
- R is the gas constant (8.314 J/(mol·K))
- T is the temperature in Kelvin (K)
- ln represents the natural logarithm

In this case, the given standard Gibbs free energy change (ΔG°) is 288.9 kJ/mol, but we need to convert it to joules per mole:

ΔG° = 288.9 kJ/mol × 1000 J/1 kJ = 288,900 J/mol

Now, let's assume the equilibrium constant for the coupled reaction is K.

Substituting the values into the equation, we have:

288,900 J/mol = -8.314 J/(mol·K) × T × ln(K)

To find the equilibrium constant K, you'll need to know the temperature (T) at which the reaction is taking place. Once you have the temperature, you can rearrange the equation to solve for K:

K = e^(-ΔG° / (RT))

where e is the base of the natural logarithm (approximately 2.71828).

Make sure you use the appropriate units for temperature (Kelvin) and gas constant (J/(mol·K)).

If you provide the temperature (in Kelvin) at which the reaction is taking place, I can help you calculate the equilibrium constant (K) correctly.