Calculate Keq: Room vs -78°C

  • Thread starter krootox217
  • Start date
  • Tags
    Calculation
In summary, the question asked about the Keq at two different temperatures and the provided equations were used to calculate the values. However, a mistake was made in using the value for ΔΔG instead of ΔG, resulting in incorrect values for Keq. Assistance is requested in solving the problem correctly.
  • #1
krootox217
51
2

Homework Statement


Hi, I have the following task:

We have two conformers and the difference in energy between them is aprox. 1 Kcal/mol. What is the Keq at room temperature vs. at -78°C?

Homework Equations



Keq=e^(deltaG/(-R*T))

The Attempt at a Solution



I tried to solve the problem the following way:

deltaG = R*T*ln(Keq) --> Keq=e^(deltaG/(-R*T))

T(room)=293.15K, T(-78°C)=195.15K
R=8.313 J/(mol*K), DeltaG= 1 Kcal/mol= 4184 J/mol

then I inserted the values and got Keq(room) = 0.18 and Keq(-78°C) = 0.08 which is apparently wrong. They told me that I used deltadeltaG instead of deltaG in the equation. Can somebody help me?
 
Physics news on Phys.org
  • #2
In the equation you quote, how is ΔG defined?
 

1. What is Keq and why is it important?

Keq, or the equilibrium constant, is a measure of the ratio of products to reactants at equilibrium in a chemical reaction. It is important because it tells us the direction and extent of a reaction under a specific set of conditions.

2. How do you calculate Keq?

Keq can be calculated by taking the ratio of the concentrations of products to the concentrations of reactants, with each concentration raised to the power of its coefficient in the balanced chemical equation. Alternatively, it can also be calculated using the equilibrium expressions for gases or for aqueous solutions.

3. What is the significance of calculating Keq at different temperatures?

Temperature can greatly affect the value of Keq for a chemical reaction. As temperature increases, the value of Keq also increases, indicating a higher concentration of products at equilibrium. Conversely, a decrease in temperature leads to a decrease in Keq, indicating a higher concentration of reactants at equilibrium.

4. How does the value of Keq change between room temperature and -78°C?

The value of Keq generally increases as temperature decreases. Therefore, at -78°C, the value of Keq would likely be higher than at room temperature. This means that there would be a higher concentration of products at equilibrium at -78°C compared to room temperature.

5. Can the value of Keq change over time?

The value of Keq does not change over time. It is a constant value at a specific temperature and set of conditions. However, the concentrations of products and reactants may change over time as the reaction proceeds towards equilibrium, which can affect the calculated value of Keq.

Similar threads

Chemical Equilibrium Constant Calculation
    • Biology and Chemistry Homework Help
Replies
1
Views
3K
Calculating time to reduce alcohol in wine using heating method
    • Chemistry
4
Replies
131
Views
4K
Evaluating False Statements on Cyclohexanol's Properties
    • Biology and Chemistry Homework Help
Replies
2
Views
2K
Atmospheric Temperature and Air Molecule Density Calculation
    • Biology and Chemistry Homework Help
Replies
8
Views
2K
Chemistry Using data (Pressure vs. density) to find molecular mass .
    • Biology and Chemistry Homework Help
Replies
7
Views
7K
Basic physics units problems involving the Ideal Gas Law
    • Introductory Physics Homework Help
Replies
5
Views
1K
Thermodynamics of a Single-Component Ideal Gas
    • Introductory Physics Homework Help
Replies
1
Views
804
Calculating Pressure & Density Proportions with Changing Altitude & Temperature
    • Introductory Physics Homework Help
Replies
19
Views
1K
Engineering Calculating the mass of air in a pressurised air tank
    • Engineering and Comp Sci Homework Help
Replies
14
Views
1K
Calculation of ΔH for Ideal Gas Processes
    • Biology and Chemistry Homework Help
Replies
11
Views
7K

Hot Threads

Recent Insights

Back
Top