Asked by Keyuri Patel on Jul 31, 2024
Verified
Consider the following substitution reaction with a ΔG° value of -91.1 kJ/mole.
HO- + CH3Cl ↔ CH3OH + Cl-
Given this information which of the following statements must be true? (R = 8.315 J/mole K)
A) The Keq at 25°C for this reaction is very large, in other words this reaction proceeds to near completion as written, left to right under standard conditions.
B) The Keq at 25°C for this reaction is very small (<1) , in other words this reaction does not proceed from left to right but rather is favored from right to left under standard conditions .
C) At 250°C the equilibrium concentration is shifted right in favor of the products (CH3OH and Cl-) . In other words there is more product than at 25°C.
D) At 250°C the equilibrium concentration of products and reactants is nearly the same.
E) Both A and C are correct.
Substitution Reaction
A type of chemical reaction where one atom or group of atoms in a molecule is replaced by another atom or group of atoms.
ΔG° Value
Represents the standard free energy change of a reaction at constant temperature and pressure, indicating the spontaneity of the process.
Standard Conditions
The set of established conditions including 0°C (273.15 K) and 1 atmosphere pressure used as a baseline to measure properties of substances.
- Acquire knowledge on the central principles of Gibbs free energy, including its components enthalpy and entropy, as they apply to chemical reactions.
- Predict the effects of temperature on reaction rates and equilibria.
Verified Answer
TL
Tasha LipfordAug 06, 2024
Final Answer :
A
Explanation :
From the given ΔG° value of -91.1 kJ/mole and using the formula ΔG° = -RTlnKeq, we can calculate Keq = e^(-ΔG°/RT). At 25°C (298 K), Keq = e^(-(-91.1*1000)/(8.315*298)) = 1.51 x 10^16. This value is very large, indicating that the reaction proceeds to near completion from left to right under standard conditions. Option A is the correct choice. Option C is incorrect since the equilibrium constant does not change with temperature.
Learning Objectives
- Acquire knowledge on the central principles of Gibbs free energy, including its components enthalpy and entropy, as they apply to chemical reactions.
- Predict the effects of temperature on reaction rates and equilibria.