F08 LS1a Pset 2keyst-1

F08 LS1a Pset 2keyst-1 - Name: TF Name: 1 LS1a Fall 08...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Name: TF Name: 1 LS1a Fall 08 Problem Set #2 Due Monday 10/6 at noon in your TFs drop box on the 2 nd floor of the Science Center 1. Shown below is a free energy diagram for the reaction (a) (4 points) On the diagram, clearly label G rxn as well as the position of equilibrium on the x-axis. Also, indicate with arrows the direction in which the reaction will proceed spontaneously at the two points (1 and 2) highlighted on the curve. (b) Is G rxn for this reaction positive or negative? Is the reaction (as written) thermodynamically favorable or unfavorable under standard state conditions? (6 points) G rxn is positve because G for the products is greater than G for the reactants. Reactions with positive free energy differences are thermodynamically unfavorable. (c) What can you say about the magnitude of K eq for this reaction? (2 points) Since the reactants are favored over the products, K eq will be less than 1. (d) What is the sign (or the value) of G rxn at equilibrium? (6 points) G rxn is a constant based on standard state conditions and typically non-equilibrium values for reactant and product concentrations. Thus the value of G rxn will not change whether or not the reaction is at equilbrium. The sign of G rxn remains positive. (e) What is the sign (or the value) of G at equilbrium? (2 points) At equilibrium, G is equal to 0. A + B C + D Name: TF Name: 2 2. Humans metabolize consumed ethanol into Acetyl-CoA, which can then be used to generate cellular energy. This process occurs in multiple steps as shown below: Ethanol Acetaldehyde Acetic Acid Acetyl-CoA Energy The first reaction in the pathway and its G rxn is shown below: Ethanol Acetaldehyde ! G rxn = +47,200 J/mol (a) Based on the value of G rxn , is the K eq for this reaction greater than 1, less than 1, or equal to 1 under standard state conditions? (2 points) K eq will be far less than one, indicating that the reactants are favored over the products. Whether or not this reaction can proceed towards the right under non-standard conditions depends on where the reaction lies with respect to equilibrium. (b) What do the magnitude of G at a particular state and the sign of G at a particular state tell us about the reaction at that particular state and its relative relationship to reaching equilibrium? (6 points) The sign of G at a particular state tells us the direction in which a reaction will proceed towards equilibrium. If the G at a particular state is less than zero (negative), then the reaction (as written) will proceed forward to equilibrium. If the G at a particular state is greater than zero (positive), the reaction will proceed backwards towards equilibrium (going forward is...
View Full Document

Page1 / 10

F08 LS1a Pset 2keyst-1 - Name: TF Name: 1 LS1a Fall 08...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online