Gibbs free energy Definition and 116 Threads

the total amount of energy able to do work is the gibbs free energy of a reaction. dG=dH-TdS according to this equation, the higher the entropy gain of a system(dS) in a reaction, the more work the system can achieve. I'm confused here. I thought entropy was the energy unable to do work?

Hi, I've recently started studying chemistry and have being going over gibbs free energy.. I understand it is a driving force causing chemical and physical changes but during my course of reading I did have some queries stem to mind. 1) In relation to equilibrium why is it that a reaction...

Homework Statement Suppose you have a mole of water at 198 K. and atmospheric pressure. use the data at the bac of this book to determine what happens to its gibbs free energy if you raise the temperature to 303 Kelvins. To compensate for this change, you could increase the pressure of the...

Homework Statement The reaction is NH_{4}Cl(s)\rightarrow NH_{3}(g)+HCl(g) \Delta H^{o}=+176 kJ and \Delta G^{o}=+91.2 kJ at 298 K What is the value of \Delta G at 1000 K? Homework Equations \Delta G=\Delta H-T\Delta S The same applies if all 'deltas' are standard The Attempt at...

Are the concepts of exergy and Gibbs Free Energy related? What are the differences between them? Thanks in advance for any help.

Homework Statement CaCO3 <-> CaO + CO2 At 900K, equilibrium pressure of CO2 is 0.0423 atm. Calculate Gibbs Free energy of Reaction and K.Homework Equations delta G = -RTlnKThe Attempt at a Solution delta G = 5656.3 cal/mol K = 0.0423 I have a feeling that this is incorrect Could someone...

Hi, I'm trying to answer a question that I'm stuck on. The question is as follows: -------------------------------------------------------------- If the Gibbs free energy change (deltaG) for ATP hydrolysis in a cell is -57 kJ/mol and the free energy change for transporting a proton from...

Homework Statement A. Explain the need for Gibbs Free Energy equation. B. Explain what it means when: \Delta G <0 \Delta G >0 \Delta G =0 Homework Equations \Delta G= \Delta H-T \Delta S The Attempt at a Solution A. Gibbs eqn comes from the need to calculate the entropy of...

Hey guys, I'm hung up on the Gibbs Free Energy equations. I know that ?G° is the free energy change under standard conditions (1 M, 1 atm, 25ºC), and that it is characteristic for a given reaction. I think that when a reaction is occurring under conditions that are not standard the equation...

Homework Statement Calculate the Gibbs free energy for a van der Waals gas (up to an integration constant), assuming a fixed amount of material and temperature. Homework Equations P = \frac{NkT}{V-Nb} - \frac{aN^2}{V^2} dG = -SdT + VdP + udN (where u is the chemical potential) The...

Homework Statement Consider fuel cell using methane as fuel. Reaction is CH^4 + 2O_2 -> 2H2O+CO_2 Assume room temperature and atmospheric temperature Determine values of delta H (Helmholtz) and delta G (Gibbs) for this reaction for one mole of methane. Question instructed the use of...

Hi I am new in thermodynamics , and I thought you can help me If it is valid dG=dW May I say dG=-Pdv P=-dG/dv? thanks in advance,Mariana P=external pressure G=Gibbs energy W=maximum work

Why must Gibbs Free Energy >0 for a reaction to occur?

I don't know where to start with this problem. I must be missing an equation or something... Q: Pb(s)+2H^{+}(aq)\rightarrow Pb^{2+}(aq)+H_2(g) \,\,\,\,\,\,\,\,E^{\degree}_{cell}=+0.126V What is the \Delta G^{\degree} in \frac{kJ}{mol} for this reaction. a) -24 b) 24 c) -12 d) 12 e) 50...

would anyone happen to know what the expression for an isothermal change in Gibbs free energy for a liquid is when the pressure changes from pi to pf. Also an expression for when its a perfect gas? i can't seem to figure them out.. and how would they be deduced? i've come across one equation...

hey i seem to be having a lot of trouble with this type of question: Calculate the change in Gibbs energy of 35g of ethanol (mass density = 0.789g cm-3) when the pressure is increased isothermally from 1 atm to 3000 atm. in my notes i have that dG=V(Pf-Pi) and search up on the net that...