Aim What is entropy Spontaneous Reaction A spontaneous
- Slides: 12
Aim: What is entropy?
Spontaneous Reaction • A spontaneous reaction is one that is able to proceed without needing an outside source of energy • A nonspontaneous reaction needs an input of energy.
Spontaneous reactions occur in the direction of: 1. Less energy (lower enthalpy): exothermic reactions are favored 2. Greater entropy (randomness, disorder)
Enthalpy (H) • In nature, reactions tend to favor a lower energy state. • Products with less Potential Energy than the reactants are favorable. • CH 4(g) + 2 O 2(g) CO 2(g) + 2 H 2 O(l) ΔH= -890. 4 KJ
Entropy
Entropy • Entropy (S); Measure of disorder or randomness in a system. In nature greater entropy is favored. • Which had greater entropy?
Entropy 1. Which phase will have the greatest entropy? The least entropy?
Entropy in Chemical Reactions • Entropy increases: 1. When the number of molecules increases during a reaction. 2. With an increase in temperature 3. When a gas is formed from a liquid or a solid. 4. When a liquid is formed from a solid.
Questions 1. Which tendencies favor a spontaneous reaction? 1) lower energy and decreasing entropy 2) lower energy and increasing entropy 3) higher energy and decreasing entropy 4) higher energy and increasing entropy
Questions 2. Which reaction system tends to become less random as reactants form products? (1) C(s) + O 2(g) --> CO 2(g) (2) S(s) + O 2(g) --> SO 2(g) (3) I 2(s) + Cl 2(g) --> 2 ICl (g) (4) 2 Mg (s) + O 2(g) --> 2 Mg. O (s)
Questions 3. As Na. Cl(s) dissolves according to the equation Na. Cl(s) --> Na+ (aq) + Cl- (aq) the entropy of the system (1) decreases (2) increases (3) remains the same
- Spontaneous reaction
- Concept of free energy
- Electrolysis spontaneous or nonspontaneous
- Which tendencies favor a spontaneous reaction
- Spontaneous reaction chemistry
- Gibbs free energy and spontaneity
- Leukoerythroblastic reaction vs leukemoid reaction
- Activity formula
- Order of reaction
- Ictahedron
- Non spontaneous process
- Entropy in thermodynamics
- Entropy change formula