# Spontainety, Entropy and Free Energy Nila Khoirul Tria Lestari
Get Started. It's Free Spontainety, Entropy and Free Energy ## 1. Thermodynamics

### 1.4. Second Law of Thermodynamics

1.4.1. The entropy of the universe increases in a spontaneous process and remains unchanged in an equilibrium process.

1.4.2. Spontaneous process: DSuniv = DSsys + DSsurr > 0

1.4.3. Equilibrium process: DSuniv = DSsys + DSsurr = 0

### 1.5. Third Law of Thermodynamics

1.5.1. The entropy of a perfect crystal at 0 K is zero

1.5.2. The entropy of a substance increases with temperature.

## 2. Spontaneous Processes

### 2.2. Spontaneous Physical and Chemical Processes in living sistem

2.2.1. A waterfall runs downhill

2.2.2. A lump of sugar dissolves in a cup of coffee

2.2.3. At 1 atm, water freezes below 0 0C and ice melts above 0 0C

2.2.4. Heat flows from a hotter object to a colder object

## 3. Entropy

### 3.3. Standard Entropy Values (S°)

3.3.1. Represent the increase in entropy that occurs when a substance is heated from 0 K to 298 K at 1 atm pressure.

3.3.1.1. ΔS°reaction = ΣnpS°products – ΣnrS°reactants

## 4. Free Energy

### 4.3. Standard Free Energy Change (ΔG°)

4.3.1. The change in free energy that will occur if the reactants in their standard states are converted to the products in their standard states.

### 4.4. Free Energy and Pressure

4.4.1. G = G° + RT ln(P) or ΔG = ΔG° + RT ln(Q)

### 4.5. The Meaning of ΔG for a Chemical Reaction

4.5.1. A system can achieve the lowest possible free energy by going to equilibrium, not by going to completion.

4.5.2. The equilibrium point occurs at the lowest value of free energy available to the reaction system.

4.5.3. ΔG = 0 = ΔG° + RT ln(K) ΔG° = –RT ln(K)

### 4.6. Change in Free Energy to Reach Equilibrium

4.6.1. DG = DG0 + RT lnQ

4.6.1.1. R is the gas constant (8.314 J/K•mol);T is the absolute temperature (K); Q is the reaction quotient

4.6.2. At Equilibrium

4.6.2.1. Delta G = 0

4.6.2.2. Q = K

4.6.2.3. 0 = DG0 + RT lnK

4.6.2.4. DG0 = - RT lnK