Free Energy Change

Question 1

What is free energy change?

Answer 1

Free energy change, deltaG,is a measure used to predict whether a reaction is feasible

Question 2

When might a reaction happen by itself?

Answer 2

When deltaG is negative or equal to 0

Question 3

What does free energy change take into account?

Answer 3

Changes in enthalpy and entropy in the system

Question 4

What is the formula for free energy change?

Answer 4

deltaG = deltaH - (temperature x deltaS)

Question 5

The feasibility of some reactions depends on temperature, explain

Answer 5

1. If a reaction is exothermic and has a positive entropy change, deltaG is always negative - these reactions are feasible at any temperature
2. If a reaction is endothermic and has a negative entropy change, deltaG is always positive - these reactions are not feasible at any temperature
3. If a reaction is endothermic and has a positive entropy change, the reaction won’t be feasible at lower temperatures but will be at a high enough temperature
4. If a reaction is exothermic and has a negative entropy change, the reaction will be feasible at lower temperatures but not at higher temperatures

Question 6

You can find the temperature a reaction is feasible when?

Answer 6

When deltaG is zero, the equation is,

T = deltaH / deltaS