PHD
  1. Inorganic chemistry  1.1. Coordination chemistry  1.1.1. Ligand field theory  1.1.2. Crystal field theory  1.1.3. Molecular Orbital Theory for Coordination Compounds  1.1.4. Stability of Coordination Compounds  1.1.5. Electronic spectra of coordination compounds  1.1.6. Isomerism in Coordination Compounds  1.1.7. Kinetics and mechanism of coordination reactions  1.2. Organometallic Chemistry  1.2.1. Metal Carbonyls  1.2.2. Metal alkyl and aryl  1.2.3. Fischer and Schrock carbonaceans  1.2.4. Oxidative Addition and Reductive Elimination  1.2.5. Metal Hydrides  1.2.6. Catalysis by organometallic compounds  1.2.7. Metallocenes and Sandwich Complexes  1.2.8. CH activation  1.3. Solid state chemistry  1.3.1. Crystal structures and lattices  1.3.2. Band theory and electrical properties  1.3.3. Defects in the crystal  1.3.4. Synthesis of solid state materials  1.3.5. Magnetic and optical properties of solids  1.3.6. Superconductivity  1.3.7. Solid state ionics  1.4. Bio-inorganic chemistry  1.4.1. Metalloproteins and enzymes  1.4.2. Metal ion transport and storage  1.4.3. The role of metals in medicine  1.4.4. Bioinspired catalysis  1.4.5. Metal–DNA interactions  1.4.6. Metal Complexes in Medical Science  1.5. Lanthanides and Actinides  1.5.1. Electronic configuration and oxidation states in lanthanides and actinides  1.5.2. Spectral and Magnetic Properties in Lanthanides and Actinides  1.5.3. Separation and Extraction of Lanthanides and Actinides  1.5.4. Coordination chemistry of f-block elements  1.6. Main Group Chemistry  1.6.1. Chemistry of boron compounds  1.6.2. Chemistry of Silicon and Germanium Compounds  1.6.3. Chemistry of Phosphorus and Sulfur Compounds  1.6.4. Organosilicon chemistry  1.6.5. Noble Gas Chemistry
  2. Organic chemistry  2.1. Reaction mechanism  2.1.1. Nucleophilic substitution reactions  2.1.2. Electrophilic addition and substitution reactions  2.1.3. Elimination reactions  2.1.4. Rearrangement reactions  2.1.5. Radical reactions  2.1.6. Pericyclic Reactions  2.1.7. Photochemical reactions  2.2. Stereoscopic  2.2.1. Chirality and optical activity  2.2.2. Structural analysis  2.2.3. Stereoelectronic effects  2.2.4. Asymmetric synthesis  2.2.5. Dynamic Stereochemistry  2.3. Organometallic Chemistry in Organic Synthesis  2.3.1. Organolithium and organomagnesium reagents  2.3.2. Transition metal catalyzed coupling reactions  2.3.3. Palladium-catalyzed reactions  2.3.4. Olefin Metathesis  2.3.5. Gold and silver catalysis  2.4. Natural products chemistry  2.4.1. Alkaloids and terpenoids  2.4.2. Steroids and Flavonoids  2.4.3. Total synthesis of natural products  2.4.4. Biosynthesis of natural products  2.5. Supramolecular Chemistry  2.5.1. Host-Guest Chemistry  2.5.2. Self-assembly and molecular recognition  2.5.3. Supramolecular Catalysis  2.5.4. Molecular Machines
  3. Physical Chemistry  3.1. Thermodynamics  3.1.1. Laws of Thermodynamics  3.1.2. Chemical Potential and Equilibrium  3.1.3. Statistical thermodynamics  3.1.4. Non-equilibrium thermodynamics  3.2. Quantum Chemistry  3.2.1. Schrödinger equation and its applications  3.2.2. Molecular orbital theory  3.2.3. Density functional theory  3.2.4. Post-Hartree–Fock methods  3.3. Chemical kinetics  3.3.1. Reaction rate theory  3.3.2. Mechanism and rate laws  3.3.3. Catalysis and enzyme kinetics  3.3.4. Reaction dynamics  3.4. Spectroscopy and molecular structure  3.4.1. Infrared Spectroscopy  3.4.2. UV-visible spectroscopy  3.4.3. Nuclear Magnetic Resonance Spectroscopy  3.4.4. Mass Spectrometry  3.4.5. Raman Spectroscopy  3.5. Surface and Colloid Chemistry  3.5.1. Absorption and Catalysis  3.5.2. Surfactants and micelles  3.5.3. Colloidal Stability  3.5.4. Nanomaterials and Interfaces
  4. Analytical chemistry  4.1. Chromatography  4.1.1. Gas Chromatography  4.1.2. High Performance Liquid Chromatography  4.1.3. Thin Layer Chromatography  4.1.4. Ion Chromatography  4.2. Electroanalytical techniques  4.2.1. Voltammetry and Polarography  4.2.2. Conductometry and potentiometry  4.2.3. Colometry  4.3. Spectroscopic Methods  4.3.1. Atomic absorption spectroscopy  4.3.2. Fluorescence Spectroscopy  4.3.3. X-ray diffraction  4.3.4. Electron paramagnetic resonance spectroscopy  4.4. Chemometrics  4.4.1. Data processing and statistical methods  4.4.2. Multidisciplinary analysis  4.4.3. Machine Learning in Analytical Chemistry
  5. Theoretical and Computational Chemistry  5.1. Molecular dynamics simulation  5.2. Quantum chemistry methods  5.3. Computational drug design  5.4. Machine Learning in Chemistry  5.5. Ab initio molecular dynamics
  6. Biophysics and Medicinal Chemistry  6.1. Drug discovery and design  6.2. Enzyme kinetics and inhibition  6.3. Chemical biology approach  6.4. Protein-ligand interactions  6.5. Bioorthogonal chemistry
  7. Materials chemistry  7.1. Polymer chemistry  7.1.1. Polymerization mechanism  7.1.2. Functional Polymers  7.1.3. Biodegradable Polymer  7.1.4. Conducting and semiconducting polymers  7.2. Nano Chemistry  7.2.1. Nanoparticles and nanostructures  7.2.2. Carbon-based nanomaterials  7.2.3. Quantum dots  7.3. Energy and Environmental Chemistry  7.3.1. Battery and Fuel Cell Chemistry  7.3.2. Green chemistry and sustainable materials  7.3.3. Photocatalysis

PHD → Physical Chemistry ↓


Thermodynamics


Thermodynamics is a branch of physical chemistry that deals with the study of energy, work, heat, and how these quantities interact with each other and affect matter. It plays a vital role in understanding various chemical processes and reactions. Thermodynamics provides the principles and framework necessary for understanding how energy exchange occurs in both natural phenomena and engineered systems.

Basic concepts

The foundation of thermodynamics lies in several fundamental concepts: system, surroundings, and boundaries. A system is the part of the universe we are interested in, while the surroundings encompass everything else. The boundary separates the system from its surroundings and can be real or imaginary. Thermodynamic systems can be open, closed, or isolated depending on their interactions with the surroundings.

Types of systems

  • Open system: exchanges both energy and matter with its surrounding environment.
  • Closed system: exchanges only energy, not matter, with its surroundings.
  • Isolated system: does not exchange energy or matter with its surroundings.

State functions and variables

State functions are properties that depend only on the current state of the system, not on how that state was reached. Common state functions include internal energy (U), enthalpy (H), entropy (S), and free energy (G). In contrast, path functions such as work and heat depend on the path taken to get from one state to another.

The state of a thermodynamic system can be described using state variables such as pressure (P), volume (V), temperature (T) and concentration. These variables are essential to understanding the behavior of the system and are interrelated through state equations.

Laws of thermodynamics

Thermodynamics is governed by four fundamental laws, known as the zeroth, first, second, and third laws of thermodynamics. Each law introduces fundamental principles about energy and entropy.

Zeroth law of thermodynamics

The zeroth law establishes the concept of temperature and thermal equilibrium. It states that if two systems are in thermal equilibrium with a third system, then they are in thermal equilibrium with each other. Mathematically, if A is in equilibrium with B, and B is in equilibrium with C, then A is in equilibrium with C

First law of thermodynamics

The first law of thermodynamics, often called the law of conservation of energy, states that energy cannot be created or destroyed; it can only change form. The change in the internal energy of a system (ΔU) is equal to the value obtained by subtracting the work done by the system (w) from the heat (q) added to the system.

ΔU = q - w

For example, when a gas in a piston is heated, it expands, doing work on the piston and gaining internal energy from the added heat.

Second law of thermodynamics

The second law introduces the concept of entropy, which is a measure of disorder or randomness in a system. It states that in any thermodynamic process, the total entropy of a system and its surroundings always increases for irreversible processes. In reversible processes, the entropy change remains constant.

Mathematically it is expressed as:

ΔS_universe = ΔS_system + ΔS_surroundings ≥ 0

This theory explains why some processes are spontaneous. For example, a cup of hot tea left in a cold room loses heat until it reaches thermal equilibrium with the room. In this spontaneous process, the entropy of the universe increases.

Third law of thermodynamics

The third law states that the entropy of an ideal crystal at absolute zero (0 K) is exactly zero. This provides a reference point for calculating entropy. As the temperature approaches absolute zero, the entropy of the system becomes minimum.

Visualization of thermodynamic processes

Thermodynamic processes often involve changes in state variables such as pressure, volume, and temperature. We can represent these processes graphically using various types of diagrams, such as pressure-volume (PV), temperature-entropy (TS), and enthalpy-entropy (HS) diagrams.

Pressure-volume diagram (PV diagram)

The PV diagram shows the relationship between the pressure and volume of a system. In these diagrams, different thermodynamic paths can be observed, such as isothermal (constant temperature), isobaric (constant pressure), isochoric (constant volume), and adiabatic (no heat exchange) processes.

Volume Pressure Adiabatic

Example: Understanding isothermal expansion

Isothermal processes occur at constant temperature. Imagine that we have an ideal gas enclosed in a piston that is in thermal contact with a heat reservoir. As the gas expands isothermally, it does work on the piston while absorbing an equal amount of heat from the reservoir to keep the temperature constant.

According to the ideal gas law:

PV = nRT

Here, P is the pressure, V is the volume, n is the number of moles, R is the gas constant, and T is the temperature. Since the temperature remains constant, the equation can be rearranged to show that pressure and volume are inversely proportional during an isothermal process:

P ∝ 1/V

Entropy change in systems

Entropy changes can provide information about the spontaneity and feasibility of chemical reactions. For example, when ice melts at 0 °C to form water, the entropy of the system increases because the structure of liquid water is more disordered than that of solid ice.

Conclusion

Thermodynamics is an important field in physical chemistry, providing the theory necessary to understand energy transformations and the direction of processes. By mastering the laws of thermodynamics and their implications, chemists can predict how systems behave under different conditions and design experiments or industrial processes that use chemical energy efficiently.

This discovery of thermodynamics opens up avenues for further studies in statistical mechanics, quantum chemistry and kinetic theory, where deeper insights into molecular interactions and energy distributions are gained. As you delve deeper into this subject, you will unveil more complex scenarios and a subtle understanding of the microscopic and macroscopic behaviours of matter.


PHD → 3.1


U
username
0%
completed in PHD

← Prev (3)
Physical Chemistry
Next (3.1.1) →
Laws of Thermodynamics

Comments 



Thermodynamics

https://www.chemistryelite.com/phd/3.1?ceal=en