Gibbs Free Energy

Gibbs free energy ΔG value will be _____ if ΔH and ΔS are the same sign (++, or --)

+/-

Gibbs free energy Energy releasing reactions have what G value?

-𐤃G

Gibbs free energy If the ΔG is ___ 0 the reaction is spontaneous

<

Gibbs free energy If the ΔH is ___ 0 the reaction is spontaneous

<

Gibbs free energy For a spontaneous process, ΔS ____ 0

>

Thermodynamics vs kinetics If the forward reaction has a ΔG>0, what is the relative energy of reactant (A) vs product (B)?

A < B (b)

Thermodynamics vs kinetics If the forward reaction has a ΔG<0, what is the relative energy of reactant (A) vs product (B)?

A > B (a)

Thermodynamics vs kinetics ____ _____ is the amount of energy required to form a high intermediate during the course of the reaction.

Activation energy (Eₐ) Is the bump

Gibbs free energy Is based off of the ideal gas law which states?

PV = nRT

Gibbs free energy During the reaction, there is a constant ____, ____ and ____

Pressure, volume, and temperature

Thermodynamics vs kinetics Kinetics: Rate is determined by the _____ _____ (energy of transition state)

activation energy

Gibbs free energy 𐤃G can be ____ but not measured

calculated

Gibbs free energy You can change an endergonic reaction under standard conditions to spontaneous how?

change concentration of products/reactants

Gibbs free energy Most biological processes occur at ____ ___

constant temp

Gibbs free energy Equation can only be used under specific conditions including...

constant temp and pressure reversible reaction only work is PV

Gibbs free energy A nonspontaneous reaction requires the input of energy, known as _____

endergonic

Gibbs free energy In our body, a +ΔG can be changed to a -ΔG to become...

energetically favorable

Gibbs free energy _____ can tell us if a reaction is spontaneous

entropy

Gibbs free energy _______ = natures tendency to create the most probably system

entropy

Thermodynamics vs kinetics Thermodynamics tell us what ____ looks like and STABILITY

equilibrium

Gibbs free energy Enthalpy tells us whether the reaction is ____ or _____, but does not specify spontaneity

exothermic or endothermic

Thermodynamics vs kinetics Activation energy (Eₐ) and ΔG are inversely related. For example, if I have a very low ΔG (<<<0), then I need a ______ Activation energy (Eₐ) for the energy to proceed

high

Gibbs free energy The heat absorbed (Q) by a reversible process is _____ than heat absorbed from an irreversible process because of friction

higher

Thermodynamics vs kinetics Activation energy (Eₐ) is the amount of energy required to form a high intermediate during the course of the reaction. When Eₐ is a _____ number, the reaction occurs SLOWER

higher

Gibbs free energy 𐤃G is measured in what units?

joules/mol

Thermodynamics vs kinetics Eₐ is talking about ____

kinetics

Gibbs free energy At a _____ temperature, particles move around less

low

Thermodynamics vs kinetics Combustion is very exothermic but occur at a very ____ ___

low rate

Gibbs free energy No _____ is exchanged, only energy is exchanged

mass

Gibbs free energy The number of _____ remains constant

mols

Gibbs free energy ΔG value will always be _____ if ΔH = - and ΔS = +

negative

Gibbs free energy ΔH value represents enthalpy, and ideally want this value to be ____ (release of energy)

negative

When enthalpy is _____ it is releasing energy, when it is ______ it is absorbing energy ΔH

negative, positive

Gibbs free energy When ΔG is > 0, it is known as a ______ reaction

non-spontaneous

Gibbs free energy ΔG value will always be _____ if ΔH = + and ΔS = +

positive

Gibbs free energy ΔS value represents entropy which we ideally want to be a _____ value

positive

Thermodynamics vs kinetics Kinetics tells us how ______ equilibrium is achieved

quickly

Gibbs free energy A positive ΔG = reaction is ______ ______ (ex a weak acid will not dissociate to a large extent)

reactant-favoured

Gibbs free energy Tells us whether what will happen?

reaction will occur

Thermodynamics vs kinetics In our bodies, many reactions require enzymes, to ______ Activation energy (Eₐ)

reduce

An ______ process = theoretically have no friction, where so close to equilibrium you can always go backwards in a reaction (doesn't actually exist in nature)

reversible

Thermodynamics vs kinetics Activation energy (Eₐ) is the amount of energy required to form a high intermediate during the course of the reaction. When Eₐ is a _____ number, the reaction occurs FASTER

smaller

Gibbs free energy A _____ reaction does not require the input of energy

spontaneous

Gibbs free energy An irreversible reaction is a ______ reaction

spontaneous

Gibbs free energy When ΔG is < 0, it is known as a ______ reaction

spontaneous

Suppose that a reaction has ΔH = -77kJ and ΔS = -0.48kJ. At what temp will it change from spontaneous to a non-spontaneous reaction? a) 47K b) 160K c) 243K d) 321K

spontaneous = <0, nonspontaneous = >0 ΔG = ΔH - T(ΔS) 0 = -77kJ - T(-0.48kJ) * convert kJ --> J 0 = -77000J - T(-480kJ) 77000J/480kJ = T 8 x 10^4/5 x 10^2 = T <2 x 10^2 = T Therefore, 160K

Thermodynamics vs kinetics Thermodynamics: If ΔH <0, the bonds of products are more _____ than reactants. THIS HAS NOTHING TO DO WITH RATE

stable

Gibbs free energy Reactions are presumed to be reversible, as enthalpy is a _____ function. ΔHforward = - ΔHreverse

state

Gibbs free energy is a ___ ___ (only cares about energy put in and taken out, not the pathway)

state function

Thermodynamics vs kinetics In our bodies, many reactions are ______ favourable, and _______ unfavourable which is why we need enzymes

thermodynamically, kinetically

Thermodynamics vs kinetics ΔG is talking about _______

thermodynamics

Gibbs free energy ΔG° describes what?

when the reaction is happening under standard conditions (products and reactants = 1 M)

Gibbs free energy Tells us what?

whether a reaction is spontaneous or not

Gibbs free energy Reaction: HCOOH --> HCOO- + H+ BOTH AT 1M of concentration ΔG° = 21.3kJ ΔG = -5kJ T = 298K (room temp) What should the Q value be for our reaction to be negative/ spontaneous product favoured?

ΔG = ΔG° + 2303RTlogQ 1. need to convert G values from kJ to J ΔG° = 21300J ΔG = -5000J ΔG = ΔG° + 2303RTlogQ -5000 = 21300 + (2303)(8.314 J)(298) logQ -21300 -5000/(2300)(8 J)(300) = logQ -26300/(2300)(2400) = logQ -2.6 x 10^4/(2.0 x 10^3)(2.5 x 10^3) = logQ -25 x 10^3/(5 x 10^6) = logQ -5 x 10^-3 = logQ (with log, swap the numbers) Q = 3 x 10^-5 This indicates that when Q = [HCOO-][H+]/[HCOOH] = 3 x 10^-5, the reaction is exergonic (spontaneous, product favoured)

Gibbs free energy CH4(g) + 2O2(g) --> CO2(g) + 2H2O (l) 186J/kmol + 205J/kmol --> 213.6 J/kmol + 69.9 J/kmol [std entropys @ 25C] ΔH= -890.3KJ is this reaction spontaneous?

ΔG = ΔH - T(ΔS) IN J: ΔS = 215 + 2(70) - [185 + 2(205)] ΔS = 215 + 140 - [185 + 410] ΔS = 355 - 595 ΔS = -240 J/K H IN KJ Convert --> 240 x 10^-3 --> -0.24 kJ/K ΔG = ΔH - T(ΔS) ΔG = -890.3KJ - 298(-0.24) ΔG = -890KJ + 300(0.25) ΔG = -890KJ + 75 ΔG = -815KJ So, it is a spontaneous reaction (<0)

Gibbs free energy equation?

ΔG = ΔH - T(ΔS) (change in energy = change in heat/enthalpy - temp x entropy)

Gibbs free energy What is the equation for enthalpy ΔH?

ΔH = Q

Gibbs free energy What is the equation to find entropy?

ΔS = Δq/T q = change in energy

Gibbs free energy The second law of thermodynamics tells us that in every real biological process, the change in entropy of the system plus change in entropy of surroundings is always greater than 0. Show this as an equation

ΔSystem + ΔSurroundings = ΔSuniverse > 0

Gibbs free energy equation? (terms of product and reactant)

𐤃G = G₂ - G₁ (change in energy = energy product - reactant)

Thermodynamics vs kinetics True or false, the more STABLE the product, the FASTER the reaction?

FALSE HAVE NOTHING TO DO WITH EACHOTHER