If free energy decreases, the reaction can proceed. If the free energy increases, the reaction can’t proceed. A reaction is favored if the free energy of the system decreases. A reaction is not favored if the free energy of the system increases.
Q. What happens to the entropy of water when it is boiling?
When the water boils, the entropy change is quite large (ΔSvaporization = 109 J/mol K), as the molecules go from being relatively constrained in the liquid to gas molecules that can fly around. At temperatures lower than the boiling point, the enthalpy term predominates and ΔG is positive.
Table of Contents
- Q. What happens to the entropy of water when it is boiling?
- Q. Can entropy ever be negative?
- Q. Is Gibbs free energy positive or negative?
- Q. Can Gibbs free energy negative?
- Q. Under what conditions will free energy change be negative?
- Q. Can Helmholtz free energy be negative?
- Q. What are sources of free energy in cells?
- Q. Does pyruvate have a lot of energy?
Q. Can entropy ever be negative?
There is no such thing as negative entropy, but a negative change in entropy exists. For example, a reaction that condenses from a gas to liquid would have a negative delta S because the liquid would occupy less possible states than the gas due to the decrease in temperature and volume.
Q. Is Gibbs free energy positive or negative?
It is the entropy term that favors the reaction. Therefore, as the temperature increases, the TΔS term in the Gibbs free energy equation will begin to predominate and ΔG will become negative….Gibbs Free Energy.
| ΔH | ΔS | ΔG |
|---|---|---|
| positive | negative | always positive |
Q. Can Gibbs free energy negative?
Yes, the Gibbs free energy can be negative or positive or zero. The sign of ΔG tells us the direction in which the reaction will shift to reach equilibrium. If ΔG=0 , Q=K , and the system is at equilibrium.
Q. Under what conditions will free energy change be negative?
This condition describes an endothermic process that involves an increase in system entropy. In this case, ΔG will be negative if the magnitude of the TΔS term is greater than ΔH. If the TΔS term is less than ΔH, the free energy change will be positive.
Q. Can Helmholtz free energy be negative?
The negative of the change in the Helmholtz energy during a process is equal to the maximum amount of work that the system can perform in a thermodynamic process in which volume is held constant.
Q. What are sources of free energy in cells?
Complex organic food molecules such as sugars, fats, and proteins are rich sources of energy for cells because much of the energy used to form these molecules is literally stored within the chemical bonds that hold them together.
Q. Does pyruvate have a lot of energy?
The C-S bond in acetyl-CoA is a high energy bond. But, the energy to form this unstable bond actually comes from the loss of the fully oxidized carboxyl group leaving pyruvate. But, having the whole carboxyl group still makes pyruvate have a higher total energy.
