Graduate
  1. Physical Chemistry  1.1. Thermodynamics  1.1.1. Laws of Thermodynamics  1.1.2. Enthalpy and heat capacity  1.1.3. Entropy and free energy  1.1.4. Phase Equilibrium  1.1.5. Statistical thermodynamics  1.1.6. Thermodynamic cycle  1.1.7. Fugacity and activity  1.2. Quantum Chemistry  1.2.1. Principles of quantum mechanics  1.2.2. Schrödinger Equation  1.2.3. Particle in a box  1.2.4. Operators and eigenvalues  1.2.5. Atomic orbitals  1.2.6. Molecular orbital theory  1.2.7. Perturbation theory  1.2.8. Valence bond theory  1.2.9. Hybridization and chemical bonding  1.3. Chemical kinetics  1.3.1. Rate laws and reaction mechanisms  1.3.2. Collision theory  1.3.3. Transition state theory  1.3.4. Enzyme Kinetics  1.3.5. Chain Reactions and Polymerization  1.3.6. Photochemical reactions  1.4. Statistical mechanics  1.4.1. Partitioning functions  1.4.2. Molecular distribution functions  1.4.3. Boltzmann Distribution  1.4.4. Bose–Einstein and Fermi–Dirac statistics  1.5. Spectroscopy  1.5.1. Rotational Spectroscopy  1.5.2. Vibrational Spectroscopy  1.5.3. Electronic Spectroscopy  1.5.4. Nuclear magnetic resonance spectroscopy  1.5.5. Mass Spectrometry  1.5.6. Raman Spectroscopy  1.5.7. Electron paramagnetic resonance spectroscopy  1.6. Surface and colloidal chemistry  1.6.1. Absorption isotherm  1.6.2. Surface tension and wetting  1.6.3. Colloidal Stability  1.6.4. Catalysis  1.6.5. Emulsions and micelles  1.7. Electrochemistry  1.7.1. Nernst equation  1.7.2. Electrochemical cells  1.7.3. Conductivity and mobility  1.7.4. War  1.7.5. Fuel cells  1.7.6. Electrolysis
  2. Organic chemistry  2.1. Reaction mechanism  2.1.1. Nucleophilic substitution reactions  2.1.2. Electrophilic addition reactions  2.1.3. Elimination reactions  2.1.4. Rearrangement reactions  2.1.5. Radical reactions  2.1.6. Pericyclic reactions  2.2. Spectroscopy and structural determination  2.2.1. UV-Vis Spectroscopy  2.2.2. IR Spectroscopy  2.2.3. NMR Spectroscopy  2.2.4. Mass Spectrometry  2.2.5. X-ray crystallography  2.3. Stereoscopic  2.3.1. Chirality and optical activity  2.3.2. Structural analysis  2.3.3. Geometrical isomerism  2.3.4. Dynamic Stereochemistry  2.4. Organometallic Chemistry  2.4.1. Organolithium and organomagnesium reagents  2.4.2. Palladium-catalyzed cross-coupling reactions  2.4.3. Transition Metal Complexes  2.4.4. Metal–carbon bond  2.5. Polymer chemistry  2.5.1. Polymerization mechanism  2.5.2. Polymer Characteristics  2.5.3. Biodegradable Polymer  2.5.4. Conducting polymer  2.5.5. Supramolecular polymers  2.6. Medicinal chemistry  2.6.1. Drug design and development  2.6.2. Pharmacokinetics and pharmacodynamics  2.6.3. Structure-activity relationships  2.6.4. Molecular docking and drug screening
  3. Inorganic chemistry  3.1. Coordination chemistry  3.1.1. Crystal field theory  3.1.2. Ligand field theory  3.1.3. Spectrochemical Series  3.1.4. Chelation and stability  3.2. Organometallic Chemistry  3.2.1. Metal Carbonyls  3.2.2. Catalysis by organometallic complexes  3.2.3. Metallocenes  3.3. Bio-inorganic chemistry  3.3.1. Metalloproteins and enzymes  3.3.2. The role of metals in biological systems  3.3.3. Metal ion transport and storage  3.4. Solid state chemistry  3.4.1. Crystal Structures  3.4.2. Band theory of solids  3.4.3. Superconductors  3.4.4. Defects in the crystal  3.5. Lanthanides and Actinides  3.5.1. Electronic configuration in lanthanides and actinides  3.5.2. Coordination chemistry of the lanthanides  3.5.3. Magnetic Properties of Lanthanides
  4. Analytical chemistry  4.1. Chromatography  4.1.1. Gas Chromatography  4.1.2. High Performance Liquid Chromatography  4.1.3. Thin Layer Chromatography  4.2. Spectroscopic Techniques  4.2.1. Atomic absorption spectroscopy  4.2.2. X-ray diffraction  4.2.3. Inductively coupled plasma spectroscopy  4.3. Electroanalytical methods  4.3.1. Potentiometry  4.3.2. Voltammetry  4.3.3. Colometry  4.4. Mass Spectrometry  4.4.1. Ionization Technique  4.4.2. Fragmentation Pattern  4.5. Chemometrics  4.5.1. Multidisciplinary analysis  4.5.2. Machine Learning in Chemistry
  5. Theoretical and Computational Chemistry  5.1. Molecular dynamics simulation  5.1.1. Force fields and energy minimization  5.1.2. Monte Carlo simulation in molecular dynamics simulations  5.2. Quantum chemical methods  5.2.1. Hartree–Fock theory  5.2.2. Density functional theory  5.2.3. Semi-empirical methods  5.3. Computational drug design  5.3.1. Molecular Docking  5.3.2. QSAR Modeling  5.3.3. Virtual Screening
  6. Biochemistry  6.1. Enzyme Kinetics  6.1.1. Michaelis-Menten kinetics  6.1.2. Inhibition mechanism  6.2. Metabolism and Bioenergetics  6.2.1. Glycolysis  6.2.2. Citric acid cycle  6.2.3. Electron transport chain  6.3. molecular Biology  6.3.1. DNA replication and repair  6.3.2. Protein synthesis  6.3.3. Gene Regulation  6.4. Structural Biochemistry  6.4.1. Protein Folding  6.4.2. Membrane Biophysics
  7. Environmental Chemistry  7.1. Atmospheric Chemistry  7.1.1. Greenhouse gases  7.1.2. Ozone depletion  7.1.3. Air pollutants and smoke  7.2. Water Chemistry  7.2.1. pH and water hardness  7.2.2. Wastewater treatment  7.2.3. Aquatic Chemistry  7.3. Soil Chemistry  7.3.1. Heavy metal contamination  7.3.2. Soil pH and Buffering  7.3.3. Nutrient cycling  7.4. Toxicology and Chemical Safety  7.4.1. Toxicokinetics  7.4.2. Risk Assessment in Toxicology and Chemical Safety in Environmental Chemistry  7.4.3. Effects of pollutants on the environment

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Physical Chemistry


Physical chemistry is a fundamental branch of chemistry that combines the principles of physics and chemistry to understand how matter behaves at the molecular and atomic level. It provides detailed explanations for various macroscopic phenomena that result from molecular interactions. Physical chemistry applies concepts such as thermodynamics, quantum mechanics, statistical mechanics, and kinetics to study and understand the physical properties of molecules and their chemical reactions.

Basic concepts

Physical chemistry has several core concepts that serve as the foundation of the subject:

1. Thermodynamics

Thermodynamics deals with the study of heat and temperature and their relation to energy and work. It describes the macroscopic behavior of systems and can be summarized with four fundamental laws:

The first law of thermodynamics states that energy cannot be created or destroyed, only transformed. This is often referred to as the energy conservation principle. The mathematical expression is:

ΔU = Q - W

where ΔU is the change in internal energy of the system, Q is the heat added to the system, and W is the work done by the system.

The second law of thermodynamics states that the total entropy of an isolated system can never decrease over time. Entropy is a measure of disorder or randomness. An example of this is the melting of ice, where the structured ice lattice transforms into more random liquid water.

Third law of thermodynamics: As the temperature approaches absolute zero, the entropy of an ideal crystal approaches zero. This shows that it is impossible to reach absolute zero in a finite number of steps.

The zeroth law of thermodynamics deals with thermal equilibrium and forms the basis of temperature measurement.

2. Quantum chemistry

Quantum chemistry applies the principles of quantum mechanics to the study of molecules. It provides a detailed understanding of how electrons are distributed in atoms and molecules, and describes the quantized nature of energy levels.

An elementary quantum mechanical model is the Schrödinger equation, which provides a way to calculate the probability distribution of electrons:

ĤΨ = EΨ

where Ĥ is the Hamiltonian operator, Ψ is the wave function, and E is the energy of the system.

NucleusE-E-

Illustration of the electron cloud model around the nucleus. In quantum chemistry, electrons are represented by probabilistic models rather than fixed orbitals.

3. Statistical mechanics

Statistical mechanics relates the microscopic states of particles to macroscopic properties such as temperature and pressure. It uses statistics to relate a set of molecular behaviors to thermodynamic properties. The Boltzmann distribution is an important concept:

P(E) = g(E)exp(-E/kT)/Z

where P(E) is the probability of a system being in a state with energy E, g(E) is the degeneracy of the state, k is the Boltzmann constant, T is the temperature, and Z is the partition function.

4. Chemical kinetics

Chemical kinetics studies the rates of chemical reactions and the factors that affect these rates. It helps to understand how quickly a reaction will proceed and what is the mechanism behind the reaction.

An important expression in kinetics is the rate law, which relates the rate of a reaction to the concentrations of the reactants:

Rate = k[A]^m[B]^n

where k is the rate constant, [A] and [B] are the concentrations of reactants, and m and n are their reaction orders, respectively.

Applications of physical chemistry

Physical chemistry has many applications in different scientific fields. Some applications include:

  • Design and synthesis of new materials.
  • Understanding and promoting efficient energy conversion in fuel cells and batteries.
  • Development of pharmaceuticals through rational drug design.
  • Environmental chemistry for pollution control and green chemistry initiative.

Examples and models

1. Ideal gas law

The ideal gas law is an important equation in physical chemistry and it provides a simple relationship between the pressure, volume, and temperature of an ideal gas:

PV = nRT

where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature.

2. Van der Waals equation

For real gases, the ideal gas law does not always apply. The van der Waals equation accounts for non-ideal behavior:

[P + a(n/V)^2](V/n - b) = RT

where a and b are constants specific to each gas, responsible for the intermolecular forces and the volume occupied by the gas molecules, respectively.

Volume (V)Pressure(P)

The graph above shows the Van der Waals curve, which highlights deviations from ideal gas behaviour, and shows how real gases interact.

3. Phase diagram

Phase diagrams are graphical representations showing the phase of a substance at different temperatures and pressures. They are indispensable in studying the properties and phase transitions of matter.

SolidLiquidGasTemperaturePressure

The phase diagram shows the relationship between temperature and pressure along with the solid, liquid, and gas phases of a substance.

Conclusion

Physical chemistry is a vast field that underlies our understanding of the chemical processes that occur within and around us. By combining concepts of physics with chemical phenomena, it allows scientists to understand complex interactions at the molecular level and develop practical applications in a variety of fields, including biology, materials science, and environmental science. As you delve deeper into the study of physical chemistry, you will find that its principles are not only central to the field of chemistry, but they also inform and influence many other scientific disciplines.


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Physical Chemistry

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