This document discusses chemical bonding concepts including:
- Valence electrons and Lewis dot structures for representative elements.
- Ionic bonding formation through electron transfer between atoms.
- Covalent bonding through electron sharing between atoms.
- Factors that influence lattice energy of ionic compounds such as charge and ion size.
- Drawing Lewis structures and evaluating formal charges to determine most likely structures.
Basic Terminology,Heat, energy and work, Internal Energy (E or U),First Law of Thermodynamics, Enthalpy,Molar heat capacity, Heat capacity,Specific heat capacity,Enthalpies of Reactions,Hess’s Law of constant heat summation,Born–Haber Cycle,Lattice energy,Second law of thermodynamics, Gibbs free energy(ΔG),Bond Energies,Efficiency of a heat engine
This document discusses the periodic table and periodic trends among the elements. It begins by outlining the ground state electron configurations of elements. It then classifies the elements and discusses how atomic and ionic radii vary periodically. The document also examines how other properties like ionization energy and electron affinity change across the periodic table. Specific trends in reactivity are described for representative main group elements in Groups 1A through 8A. In summary, the key periodic trends and relationships among atomic and physical properties of the elements are outlined.
Materials Modelling: From theory to solar cells (Lecture 1)cdtpv
This document provides an overview of a mini-module on materials modelling for solar energy applications. It introduces the lecturers and outlines the course structure, which includes lectures on modelling, interfaces, and multi-scale approaches. It also describes a literature review activity where students will present a research paper using materials modelling in photovoltaics. Recommended textbooks are provided on topics like bonding in solids, computational chemistry, and density functional theory for solids.
1. DFT+U is a method that adds Hubbard corrections to DFT to better account for localized electrons and electronic correlations in transition metal oxides that LDA/GGA cannot describe accurately.
2. It introduces an on-site Coulomb repulsion term U to the energy functional that favors electron localization and integer orbital occupations.
3. The U parameter can be computed using linear response theory by perturbing occupation matrices and evaluating screened response matrices in a supercell calculation.
The document describes a practical session on DFT+U calculations. It discusses calculations on FeO using GGA and GGA+U to find insulating and metallic states. It also covers calculating the Hubbard U parameter for NiO using linear response and extrapolating to larger supercells. Finally, it proposes an exercise to perform GGA, GGA+U calculations on Cu2O, calculate the U parameter, and investigate changes to the density of states.
The document provides an overview of the electronic band structure of solids from both the Sommerfeld and Bloch perspectives. It discusses key concepts such as:
1) Quantum numbers that label the eigenenergies and eigenfunctions of the Hamiltonian.
2) Bloch's theorem which describes the wavefunction of an electron as a plane wave modulated by a periodic function with the periodicity of the crystal lattice.
3) The band structure and energy levels that arise from Bloch's treatment, which has no simple explicit form unlike Sommerfeld's free electron model.
4) Key differences between the Sommerfeld and Bloch approaches regarding concepts like the density of states, Fermi surface, and wavefunctions
UCSD NANO 266 Quantum Mechanical Modelling of Materials and Nanostructures is a graduate class that provides students with a highly practical introduction to the application of first principles quantum mechanical simulations to model, understand and predict the properties of materials and nano-structures. The syllabus includes: a brief introduction to quantum mechanics and the Hartree-Fock and density functional theory (DFT) formulations; practical simulation considerations such as convergence, selection of the appropriate functional and parameters; interpretation of the results from simulations, including the limits of accuracy of each method. Several lab sessions provide students with hands-on experience in the conduct of simulations. A key aspect of the course is in the use of programming to facilitate calculations and analysis.
This document discusses chemical bonding concepts including:
- Valence electrons and Lewis dot structures for representative elements.
- Ionic bonding formation through electron transfer between atoms.
- Covalent bonding through electron sharing between atoms.
- Factors that influence lattice energy of ionic compounds such as charge and ion size.
- Drawing Lewis structures and evaluating formal charges to determine most likely structures.
Basic Terminology,Heat, energy and work, Internal Energy (E or U),First Law of Thermodynamics, Enthalpy,Molar heat capacity, Heat capacity,Specific heat capacity,Enthalpies of Reactions,Hess’s Law of constant heat summation,Born–Haber Cycle,Lattice energy,Second law of thermodynamics, Gibbs free energy(ΔG),Bond Energies,Efficiency of a heat engine
This document discusses the periodic table and periodic trends among the elements. It begins by outlining the ground state electron configurations of elements. It then classifies the elements and discusses how atomic and ionic radii vary periodically. The document also examines how other properties like ionization energy and electron affinity change across the periodic table. Specific trends in reactivity are described for representative main group elements in Groups 1A through 8A. In summary, the key periodic trends and relationships among atomic and physical properties of the elements are outlined.
Materials Modelling: From theory to solar cells (Lecture 1)cdtpv
This document provides an overview of a mini-module on materials modelling for solar energy applications. It introduces the lecturers and outlines the course structure, which includes lectures on modelling, interfaces, and multi-scale approaches. It also describes a literature review activity where students will present a research paper using materials modelling in photovoltaics. Recommended textbooks are provided on topics like bonding in solids, computational chemistry, and density functional theory for solids.
1. DFT+U is a method that adds Hubbard corrections to DFT to better account for localized electrons and electronic correlations in transition metal oxides that LDA/GGA cannot describe accurately.
2. It introduces an on-site Coulomb repulsion term U to the energy functional that favors electron localization and integer orbital occupations.
3. The U parameter can be computed using linear response theory by perturbing occupation matrices and evaluating screened response matrices in a supercell calculation.
The document describes a practical session on DFT+U calculations. It discusses calculations on FeO using GGA and GGA+U to find insulating and metallic states. It also covers calculating the Hubbard U parameter for NiO using linear response and extrapolating to larger supercells. Finally, it proposes an exercise to perform GGA, GGA+U calculations on Cu2O, calculate the U parameter, and investigate changes to the density of states.
The document provides an overview of the electronic band structure of solids from both the Sommerfeld and Bloch perspectives. It discusses key concepts such as:
1) Quantum numbers that label the eigenenergies and eigenfunctions of the Hamiltonian.
2) Bloch's theorem which describes the wavefunction of an electron as a plane wave modulated by a periodic function with the periodicity of the crystal lattice.
3) The band structure and energy levels that arise from Bloch's treatment, which has no simple explicit form unlike Sommerfeld's free electron model.
4) Key differences between the Sommerfeld and Bloch approaches regarding concepts like the density of states, Fermi surface, and wavefunctions
UCSD NANO 266 Quantum Mechanical Modelling of Materials and Nanostructures is a graduate class that provides students with a highly practical introduction to the application of first principles quantum mechanical simulations to model, understand and predict the properties of materials and nano-structures. The syllabus includes: a brief introduction to quantum mechanics and the Hartree-Fock and density functional theory (DFT) formulations; practical simulation considerations such as convergence, selection of the appropriate functional and parameters; interpretation of the results from simulations, including the limits of accuracy of each method. Several lab sessions provide students with hands-on experience in the conduct of simulations. A key aspect of the course is in the use of programming to facilitate calculations and analysis.
This document discusses thermodynamics concepts including entropy, spontaneity, Gibbs free energy, and how to use thermodynamic data to determine if chemical reactions are spontaneous. It provides examples of calculating entropy changes, Gibbs free energy changes, and using these values along with enthalpy changes to predict spontaneity. Standard enthalpy and entropy values are used from data tables to perform sample calculations for reactions.
Density functional theory (DFT) provides an alternative approach to calculate properties of molecules by working with electron density rather than wave functions. DFT relies on two theorems linking the ground state energy and electron density. Approximations must be made for the exchange-correlation functional, with popular approximations including LDA, GGA, and hybrid functionals. DFT calculations can determine properties like molecular geometries, energies, vibrational frequencies, and more using software packages. While computationally efficient, DFT has limitations such as its reliance on approximate exchange-correlation functionals.
1) Einstein's mass-energy equivalence relation E=mc^2 relates mass and energy. One atomic mass unit (amu) is defined as 1/12 the mass of one carbon-12 atom, which is 1.6605x10-27 kg.
2) The binding energy of a nucleus is the energy required to break it into protons and neutrons. It is related to the mass defect based on differences in nuclear and nucleon masses. Binding energy per nucleon is highest for mid-sized nuclei like iron-56.
3) The binding energy curve shows binding energy per nucleon peaks around mass numbers 4, 8, 12, 16 and 20, which have even numbers of protons and neutrons.
1) The document discusses harmonic oscillators and how the electric dipole moment operator is used to determine selection rules for vibrational transitions observed in infrared spectroscopy.
2) It explains how the frequency of IR stretching vibrations depends on bond strength and reduced mass, and provides examples of functional groups observed in IR spectra.
3) It also discusses anharmonic oscillators and how the Morse potential is used to model molecular vibrations at higher excitation energies than the harmonic oscillator approximation.
Marie Curie discovered radioactivity through her work on atoms and their structure. Nuclear reactions involve changes to the nucleus through loss of particles and rearrangement of protons and neutrons, releasing significant energy. There are three main types of radiation emitted in radioactive decay: alpha, beta, and gamma. Half-life refers to the time it takes for half of a radioactive sample to decay and is used in radioactive dating. Radiation is dangerous as it can ionize atoms and damage DNA, disrupting cells.
Reference,
https://en.wikipedia.org/wiki/Term_symbol
James E. Huheey, Ellen A. Keiter, Richard L.Keiter and Okhil K. Medhi, Inorganic Chemistry, Principles of Structure and Reactivity. 4th Edn. Pearsons
Heterostructures, HBTs and Thyristors : Exploring the "different"Shuvan Prashant
The document discusses heterostructures, heterojunction bipolar transistors (HBTs), and thyristors. It begins by explaining homojunctions and heterojuctions, how they differ in material composition and resulting energy band structures. It then describes HBTs, noting they can achieve higher speeds than bipolar junction transistors (BJTs) due to reduced injection of minority carriers into the emitter. Finally, it discusses thyristors, four-layer pnpn semiconductor devices that can operate in either conducting or blocking states, and diacs, bidirectional thyristor variants used in alternating current switching applications.
Parameters for Classical Force Fields, E. TajkhorshidTCBG
This document discusses force field parameters for molecular dynamics (MD) simulations. It covers topology and parameter files, which contain information like atom types, bonds, angles, and nonbonded parameters that an MD code uses. It describes how to make topology files for ligands, cofactors, and special residues and how to develop missing parameters. It also explains the functional forms of bonded (bond, angle, dihedral) and nonbonded (electrostatic, van der Waals) terms in the CHARMM force field. Finally, it provides guidance on obtaining parameters from literature or other sources, transferring parameters through analogy, and optimizing parameters to fit experimental data or quantum calculations when needed to parameterize new systems for MD simulations.
This document provides an overview of chemical thermodynamics, including:
- The first law of thermodynamics which states that change in internal energy equals heat added plus work done.
- The second law of thermodynamics which states that the entropy of the universe increases for spontaneous processes.
- How changes in entropy and free energy determine whether processes are spontaneous, with spontaneous processes favoring higher entropy and more negative free energy.
The document discusses molecular geometry and hybridization of atomic orbitals. It introduces the valence shell electron pair repulsion (VSEPR) model, which predicts molecular geometry based on electron pair repulsions. Molecular geometry is determined by counting bonding pairs and lone pairs on the central atom. Hybridization involves mixing atomic orbitals to form new hybrid orbitals and explains the geometry of molecules like methane and boron trifluoride. Polar molecules form if there is an uneven distribution of charge, while nonpolar molecules have symmetrical charge distribution.
The document provides an introduction to computational quantum chemistry, including:
- Definitions of computational chemistry and computational quantum chemistry, which focuses on solving the Schrodinger equation for molecules.
- An overview of methods like ab initio quantum chemistry, density functional theory, and approximations like the Born-Oppenheimer approximation and basis set approximations.
- Descriptions of approaches like Hartree-Fock, configuration interaction, Møller-Plesset perturbation theory, and coupled cluster theory for including electron correlation effects.
Density functional theory (DFT) and the concepts of the augmented-plane-wave ...ABDERRAHMANE REGGAD
Density functional theory (DFT) is a quantum mechanical method used to investigate the electronic structure of materials. The document discusses DFT and the linearized augmented plane wave plus local orbital (LAPW+lo) method implemented in the Wien2k software. Wien2k is widely used to study the properties of solids and surfaces using an all-electron, relativistic, and full-potential DFT approach. The document provides an overview of the theoretical foundations of DFT and LAPW methods as well as examples of applications studied with Wien2k.
In computational physics and Quantum chemistry, the Hartree–Fock (HF) method also known as self consistent method is a method of approximation for the determination of the wave function and the energy of a quantum many-body system or many electron system in a stationary state
This document summarizes the research activities of J. Fontcuberta and their institution related to multiferroic materials. It discusses several research areas including new multiferroic materials and devices, double perovskites, multifunctional heterostructures on silicon, and magnetophotonic materials. Several references to recent publications are provided for some of the research areas. The overall focus is on the exploration and development of novel multiferroic materials with applications in multiple memories, logic, optical components, and electric/magnetic control of material properties.
The document discusses entropy from statistical and thermodynamic perspectives. It defines entropy statistically as the natural logarithm of the number of microscopic configurations of a system. The document outlines how entropy is a state function that always increases for irreversible processes according to the second law of thermodynamics. It also discusses how entropy is additive for combined systems and how the conditions of thermal, mechanical, and chemical equilibrium can be defined in terms of entropy being maximized. The Gibbs paradox regarding mixing of ideal gases is also summarized.
Quantum mechanics is a branch of physics that deals with phenomena at microscopic scales, describing the wavelike and particle-like behavior of energy and matter. Erwin Schrödinger developed the wave equation and Schrödinger equation, which provide a mathematical description of quantum systems. Werner Heisenberg, Max Born, and Pascual Jordan created an equivalent formulation of quantum mechanics called matrix mechanics, which is the basis of Dirac's bra-ket notation for the wave function.
An atom is the smallest particle of an element that retains the chemical properties of that element. Atoms themselves are made up of even smaller particles called subatomic particles, which include protons, neutrons, and electrons. Protons and neutrons are found in the center of the atom in the nucleus, while electrons orbit around the outside of the nucleus. The number of protons in the nucleus determines which element an atom is, while the number of neutrons can vary between atoms of the same element.
This document provides an overview of atomic structure and electron configurations in chemistry. It defines key terms like atoms, electrons, energy levels, subshells and orbitals. It explains the organization of electrons according to the Aufbau principle, Hund's rule and Pauli exclusion principle. Electron configurations are represented using boxes and arrows, spectroscopic notation and noble gas notation. The document also discusses ion formations and exceptions to the rules, along with quantum numbers that describe electron location.
This document discusses thermodynamics concepts including entropy, spontaneity, Gibbs free energy, and how to use thermodynamic data to determine if chemical reactions are spontaneous. It provides examples of calculating entropy changes, Gibbs free energy changes, and using these values along with enthalpy changes to predict spontaneity. Standard enthalpy and entropy values are used from data tables to perform sample calculations for reactions.
Density functional theory (DFT) provides an alternative approach to calculate properties of molecules by working with electron density rather than wave functions. DFT relies on two theorems linking the ground state energy and electron density. Approximations must be made for the exchange-correlation functional, with popular approximations including LDA, GGA, and hybrid functionals. DFT calculations can determine properties like molecular geometries, energies, vibrational frequencies, and more using software packages. While computationally efficient, DFT has limitations such as its reliance on approximate exchange-correlation functionals.
1) Einstein's mass-energy equivalence relation E=mc^2 relates mass and energy. One atomic mass unit (amu) is defined as 1/12 the mass of one carbon-12 atom, which is 1.6605x10-27 kg.
2) The binding energy of a nucleus is the energy required to break it into protons and neutrons. It is related to the mass defect based on differences in nuclear and nucleon masses. Binding energy per nucleon is highest for mid-sized nuclei like iron-56.
3) The binding energy curve shows binding energy per nucleon peaks around mass numbers 4, 8, 12, 16 and 20, which have even numbers of protons and neutrons.
1) The document discusses harmonic oscillators and how the electric dipole moment operator is used to determine selection rules for vibrational transitions observed in infrared spectroscopy.
2) It explains how the frequency of IR stretching vibrations depends on bond strength and reduced mass, and provides examples of functional groups observed in IR spectra.
3) It also discusses anharmonic oscillators and how the Morse potential is used to model molecular vibrations at higher excitation energies than the harmonic oscillator approximation.
Marie Curie discovered radioactivity through her work on atoms and their structure. Nuclear reactions involve changes to the nucleus through loss of particles and rearrangement of protons and neutrons, releasing significant energy. There are three main types of radiation emitted in radioactive decay: alpha, beta, and gamma. Half-life refers to the time it takes for half of a radioactive sample to decay and is used in radioactive dating. Radiation is dangerous as it can ionize atoms and damage DNA, disrupting cells.
Reference,
https://en.wikipedia.org/wiki/Term_symbol
James E. Huheey, Ellen A. Keiter, Richard L.Keiter and Okhil K. Medhi, Inorganic Chemistry, Principles of Structure and Reactivity. 4th Edn. Pearsons
Heterostructures, HBTs and Thyristors : Exploring the "different"Shuvan Prashant
The document discusses heterostructures, heterojunction bipolar transistors (HBTs), and thyristors. It begins by explaining homojunctions and heterojuctions, how they differ in material composition and resulting energy band structures. It then describes HBTs, noting they can achieve higher speeds than bipolar junction transistors (BJTs) due to reduced injection of minority carriers into the emitter. Finally, it discusses thyristors, four-layer pnpn semiconductor devices that can operate in either conducting or blocking states, and diacs, bidirectional thyristor variants used in alternating current switching applications.
Parameters for Classical Force Fields, E. TajkhorshidTCBG
This document discusses force field parameters for molecular dynamics (MD) simulations. It covers topology and parameter files, which contain information like atom types, bonds, angles, and nonbonded parameters that an MD code uses. It describes how to make topology files for ligands, cofactors, and special residues and how to develop missing parameters. It also explains the functional forms of bonded (bond, angle, dihedral) and nonbonded (electrostatic, van der Waals) terms in the CHARMM force field. Finally, it provides guidance on obtaining parameters from literature or other sources, transferring parameters through analogy, and optimizing parameters to fit experimental data or quantum calculations when needed to parameterize new systems for MD simulations.
This document provides an overview of chemical thermodynamics, including:
- The first law of thermodynamics which states that change in internal energy equals heat added plus work done.
- The second law of thermodynamics which states that the entropy of the universe increases for spontaneous processes.
- How changes in entropy and free energy determine whether processes are spontaneous, with spontaneous processes favoring higher entropy and more negative free energy.
The document discusses molecular geometry and hybridization of atomic orbitals. It introduces the valence shell electron pair repulsion (VSEPR) model, which predicts molecular geometry based on electron pair repulsions. Molecular geometry is determined by counting bonding pairs and lone pairs on the central atom. Hybridization involves mixing atomic orbitals to form new hybrid orbitals and explains the geometry of molecules like methane and boron trifluoride. Polar molecules form if there is an uneven distribution of charge, while nonpolar molecules have symmetrical charge distribution.
The document provides an introduction to computational quantum chemistry, including:
- Definitions of computational chemistry and computational quantum chemistry, which focuses on solving the Schrodinger equation for molecules.
- An overview of methods like ab initio quantum chemistry, density functional theory, and approximations like the Born-Oppenheimer approximation and basis set approximations.
- Descriptions of approaches like Hartree-Fock, configuration interaction, Møller-Plesset perturbation theory, and coupled cluster theory for including electron correlation effects.
Density functional theory (DFT) and the concepts of the augmented-plane-wave ...ABDERRAHMANE REGGAD
Density functional theory (DFT) is a quantum mechanical method used to investigate the electronic structure of materials. The document discusses DFT and the linearized augmented plane wave plus local orbital (LAPW+lo) method implemented in the Wien2k software. Wien2k is widely used to study the properties of solids and surfaces using an all-electron, relativistic, and full-potential DFT approach. The document provides an overview of the theoretical foundations of DFT and LAPW methods as well as examples of applications studied with Wien2k.
In computational physics and Quantum chemistry, the Hartree–Fock (HF) method also known as self consistent method is a method of approximation for the determination of the wave function and the energy of a quantum many-body system or many electron system in a stationary state
This document summarizes the research activities of J. Fontcuberta and their institution related to multiferroic materials. It discusses several research areas including new multiferroic materials and devices, double perovskites, multifunctional heterostructures on silicon, and magnetophotonic materials. Several references to recent publications are provided for some of the research areas. The overall focus is on the exploration and development of novel multiferroic materials with applications in multiple memories, logic, optical components, and electric/magnetic control of material properties.
The document discusses entropy from statistical and thermodynamic perspectives. It defines entropy statistically as the natural logarithm of the number of microscopic configurations of a system. The document outlines how entropy is a state function that always increases for irreversible processes according to the second law of thermodynamics. It also discusses how entropy is additive for combined systems and how the conditions of thermal, mechanical, and chemical equilibrium can be defined in terms of entropy being maximized. The Gibbs paradox regarding mixing of ideal gases is also summarized.
Quantum mechanics is a branch of physics that deals with phenomena at microscopic scales, describing the wavelike and particle-like behavior of energy and matter. Erwin Schrödinger developed the wave equation and Schrödinger equation, which provide a mathematical description of quantum systems. Werner Heisenberg, Max Born, and Pascual Jordan created an equivalent formulation of quantum mechanics called matrix mechanics, which is the basis of Dirac's bra-ket notation for the wave function.
An atom is the smallest particle of an element that retains the chemical properties of that element. Atoms themselves are made up of even smaller particles called subatomic particles, which include protons, neutrons, and electrons. Protons and neutrons are found in the center of the atom in the nucleus, while electrons orbit around the outside of the nucleus. The number of protons in the nucleus determines which element an atom is, while the number of neutrons can vary between atoms of the same element.
This document provides an overview of atomic structure and electron configurations in chemistry. It defines key terms like atoms, electrons, energy levels, subshells and orbitals. It explains the organization of electrons according to the Aufbau principle, Hund's rule and Pauli exclusion principle. Electron configurations are represented using boxes and arrows, spectroscopic notation and noble gas notation. The document also discusses ion formations and exceptions to the rules, along with quantum numbers that describe electron location.
2. Energia
Zdolność do wykonywania pracy
lub do produkowania ciepła
3. Praca objętościowa
praca = siła · odległość 06_73
P=
F
A
F
P =
W = F ⋅ ∆h N ⋅m = J
A
A
Area = A
ciśnienie = siła/powierzchnia ∆h ∆h
∆V
F N
p=
A m2 (a) Initial
state
(b) Final
state
a) Tłok przesuwa się o odległość ∆h pod
W = − p ⋅ A ⋅ ∆h wpływem ciśnienia wewn. P - układ
wykonuje pracę na otoczeniu
N 2 b) Zmiana objętości jest dana wzore ∆h x
W = − p ⋅ ∆V 2
m m = Nm = J A = ∆V
m
4. Ciepło i temperatura
Temperatura – przypadkowe ruchy
cząstek – energia kinetyczna cząstek
Film5- mikroskopowe ujęcie temperatury.MOV
Ciepło – przekazywanie energii
pomiędzy 2 ciałami spowodowany
różnicą temperatur pomiędzy nimi
Film6 gazy - mechanizm przekazywania ciepła.MOV
5. Ciepło reakcji
CH4(g) + 2O2(g) →
Energia potencjalna elektronów w
CH4(g) + 2O2(g) →
Energia wiązaniach elektronów w
substraty
substraty ∆E
potencjalna
∆Ep p
wiązaniach
egzotermiczna CO2(g) + 2H2O(g)+890 kJ
egzotermiczna CO2(g) + 2H2O(g)+890 kJ
produkty
produkty
Układ reakcyjny
Układ reakcyjny
Energia potencjalna elektronów w
2NO2
2NO2 (g) (g)
Energia wiązaniach elektronów w
produkty
produkty
∆E
potencjalna
∆Ep p
wiązaniach
N2(g) + O2(g) + 68 kJ → endotermiczna
N2(g) + O2(g) + 68 kJ → endotermiczna
substraty
substraty
6. Ciepło reakcji
Entalpia reakcji odwrotnej jest,
co do wartości taka sama jak
reakcji pierwotnej, tylko
przeciwnego znaku
CH4(g) + 2O2(g) → CO2(g) +
2H2O(l)
ΔH = – 890 kJ
CO2(g) + 2H2O(l) → CH4(g) +
2O2(g)
ΔH = 890 kJ
7. Układ i otoczenie
Układ/System: wycinek
UKŁAD
rzeczywistości (materialnego
UKŁAD
Otwarty - rzeka
świata), na której Otwarty - rzeka
Zamknięty – butla z gazem
koncentrujemy uwagę Zamknięty – butla z gazem
Izolowany – kawa w termosie
Izolowany – kawa w granit
Wieloskładnikowy - termosie
Wieloskładnikowy - -granit
Jednoskładnikowy woda
Jednoskładnikowysolona woda
Homogeniczny – - woda
Homogeniczny – – topniejący
Heterogeniczny solona woda
Heterogeniczny – topniejący
śnieg
śnieg
Otoczenie/Surroundings:
wszystko poza układem
Jakie są przemiany energii pomiędzy układem i otoczeniem?
8. Prawo zachowania energii
Energia zmienia swoją postać
i nie może powstać ani zniknąć
Suma energii układu jest stała
9. I zasada termodynamiki
Energia wewnętrzna układu izolowanego
jest stała
U = const
∆U = O
Co to jest energia wewnętrzna?
10. Funkcje stanu
Ich wartości zależą jedynie od
aktualnego stanu układu
Zmiany ich wartości nie zależą
od drogi, którą przebył układ,
aby ze stanu początkowego
osiągnąć stan końcowy
U jest funkcją stanu
11. Energia wewnętrzna
∆U = Q + W
W = - p · ∆V
∆U = zmiana energii wewnętrznej układu
Q = ciepło
W = praca
12. Entalpia
H = U + pV definicja
∆H = ∆U + p∆V i p=const
∆H = Qp + W + p∆V
∆H = Qp – p∆V + p∆V
∆H= QP i p=const
H jest funkcją stanu
Entalpia opisuje przemiany energetyczne układu
w warunkach stałego ciśnienia
13. Energia wewnętrzna
∆H ⇒przepływ energii w postaci ciepła
przez analogię
QV = ∆U i V=const
U jest funkcją stanu
Energia wewnętrzna opisuje przemiany energetyczne układu
w warunkach stałej objętości
14. Pomiar ciepła
Pojęcia
Pojemność cieplna
cieplo zaabsorbowane J J
C= o
=
wzrost temperatury C K
Ciepło właściwe, Cwł (specific heat capacity)
pojemność cieplna na gram subst.
(J/°C⋅g lub J/K⋅g)
Ciepło molowe właściwe, Cmol (molar heat capacity)
pojemność cieplna na mol subst.
(J/°C⋅mol lub J/K⋅mol)
15. Pomiar ciepła
Obliczenia
J
Q = m ⋅ Cwl ∆T (g ⋅ K = J)
g⋅K
J
Q = n ⋅ Cmol ∆T (mol ⋅ K = J)
mol ⋅ K
Q J
C=
∆T K
C J
Cwl =
g⋅K
m
C J
Cmol =
n mol ⋅ K
17. Pomiar ciepła V =const
Przykład 1 – Wyznaczanie ciepła spalania metanu
0.800g CH4 spalono w stałej objętości w nadmiarze tlenu wewnątrz
kalorymetru zawierającego 3.250⋅103 g wody. Temperatura wody wzrosła o
3.3oC . Ciepło właściwe wody wynosi 4.177 J/g⋅K. Oblicz ciepło spalania
metanu. Ciepło pochłonięte przez wodę
Q = m ⋅ Cwl ∆T (J )
J
Q = 3.250 ⋅ 103 g ⋅ 4.177 3.3K = 44798 J
g⋅K
Ciepło wydzielone przy spaleniu 1 g CH4
Q 44798 J
Qm = = = 55998
mCH 4 0.800 g
Ciepło wydzielone przy spaleniu 1 mola CH4
J g J kJ
Qmol = Qm ⋅ M CH 4 = 55998 ⋅16.02 = 897088 ≈ 9.0 ⋅10 2
g mol mol mol
18. Pomiar ciepła V =const
Przykład 1 – Wyznaczanie ciepła spalania metanu cd.
J g J kJ
Qmol = Qm ⋅ M CH 4 = 55998 ⋅ 16.02 = 897088 ≈ 9.0 ⋅ 102
g mol mol mol
19. Pomiar ciepła p =const
termometr
Kalorymetria
mieszadło
– pręcik szklany
korek
∆H rea = Qrea = −Qr
Qr = mr ⋅ Cwl ,r ⋅ ∆T
kubek styropianowy
20. Pomiar ciepła p =const
Przykład 2 – Wyznaczanie ciepła reakcji zobojętniania
Zmieszano 50 cm3 1.00 M roztworu HCl i 50 cm3 1.00 M roztworu NaOH.
Temperatura roztworu wzrosła z 25oC do 31.9oC. Oblicz ciepło zobojętniania
1 mola HCl. Ciepło właściwe wody wynosi 4.18 J/g⋅oC.
HCl + NaOH→ NaCl + H2O
H+ + OH- → H2O
21. Pomiar ciepła p =const
Przykład 2 – Wyznaczanie ciepła reakcji zobojętniania
∆H rea = −Qr = mr ⋅ Cwl ,r ⋅ ∆T
g
mr = Vr ⋅ d r ≈ Vr ⋅ d H 2O = 100cm ⋅1.0
3
3
= 100 g
cm
Cwl ,r ≈ Cwl ,H 2O
∆T = 31.9°C − 25.0°C = 6.9°C > 0
J
∆H rea = −100 g ⋅ 4.18 ⋅ 6.9°C = −2.884 kJ
g ⋅ °C
22. Pomiar ciepła p =const
Przykład 2 – Wyznaczanie ciepła reakcji zobojętniania cd.
nHCl mol
CM = M = 3
⇒ nHCl = Vr ⋅ C M
Vr dm
mol
nHCl = 0.05dm ⋅1 3 = 0.05mol
3
dm
∆H rea 2.884 kJ
∆H mol = =− = −57.68 ≈ −58
nHCl 0.05 mol
23. Prawo Hessa
substraty → produkty + ∆Hrea
Zmiana entalpii reakcji nie zależy od tego czy
reakcja przebiega w jednym czy też w kilku
aktach
Entalpia jest funkcją stanu!
25. Prawo Hessa - konsekwencje
1. Jeżeli reakcja ma przebiek odwrotny, to ∆H ma znak przeciwny
N2(g) + O2(g) → 2NO(g) ∆H = 180 kJ
2NO(g) → N2(g) + O2(g) ∆H = −180 kJ
2. Jeżeli współczynniki stechiometryczne reakcji są przemnożone przez liczbę
naturalną, to ∆H zwiększa się tyle samo razy
6NO(g) → 3N2(g) + 3O2(g) ∆H = −540 kJ
3. Jeżeli daną reakcję (spalanie węgla) da się przedstawić jako kombinację innych
reakcji (suma reakcji 1) i 2)) to ∆H jest taką samą kombinacją entalpii reakcji
składowych (∆H1+ ∆H2)
bezpośrednio etapami
C(s) + O2(g) → CO2(g) + 394 kJ 1) C(s) + ½ O2(g) → CO (g) + 110 kJ
2) CO(s) + ½ O2(g) → CO2 (g) + 284 kJ
C(s) + O2(g) → CO2(g) + 394 kJ
26. Ciepła tworzenia
pierwiastki
Jak zastosować to prawo?
∆Hso ∆H p o
Jeżeli substratami są pierwiastki
w stanie standardowym (25oC,
substraty → produkty
1013 hPa), to zmianę entalpii w
czasie syntezy danego związku
∆Hrea
(też w stanie standardowym)
nazywamy ciepłem tworzenia
Z zasady zachowania energii
∆Hso + ∆Hrea - ∆H po = 0
∆H rea =
w ogólności ∆H po- ∆H so
∆Hrea° = Σ ni∆Hi°(p) − Σnj∆Hj°(s)
27. Stan standardowy
Związek
- Gaz - ciśnienie 1 atm, 1013 hPa
- Roztwór - stężenie 1 mol/dm3
Pierwiastek
- Forma w której występuje [N2(g), K(s)]
pod ciśnieniem 1 atm i w 25°C
29. Obliczanie ciepła reakcji z entalpii
tworzenia
Przykład 3
Mając dane entalpie tworzenia, oblicz standardową
entalpię następującej reakcji:
2Al(s) + Fe2O3(s) → Al2O3(s) + 2Fe(s)
∆Hrea° = Σ ni∆Hi°(p) − Σnj∆Hj°(s)
∆H°(Fe2O3) = - 826 kJ/mol
∆H°(Al2O3) = -1676 kJ/mol
∆H°(Fe) =∆H°(Al) = 0
Film 1_termochemia_Fe2O3.MOV
30. Obliczanie ciepła reakcji z entalpii
tworzenia
Przykład 3
∆Hrea° = ∆H°(Al2O3) − ∆H°(Fe2O3)=
= -1676 kJ – (- 826 kJ) =
= - 850 kJ
31. Energie wiązań
Energia wiązania, EB (bond energy) - ilość
energii potrzebna do zerwania wiązania
pomiędzy atomami i ich przeniesienia w stan
gazowy
A - B( g ) + bond energy → A ( g ) + B( g )
H - Cl ( g ) + 432 kJ mol → H ( g ) + Cl ( g )
EB, kJ/mol
CH4(g)→ CH3(g)+ H(g) 435
CH3(g)→ CH2(g)+ H(g) 453
CH2(g)→ CH (g)+ H(g) 425
CH=(g)→ C(g)+ H(g) 339
Średnia 413
34. Energia wiązania i entalpia
tworzenia
EB pierwiastki EB
∆Hso ∆Hpo
substraty → produkty
∆Hrea
Z zasady zachowania energii
35. Obliczenia ciepła reakcji z energii
wiązań
Dla reakcji w stanie gazowym
∆H 0
rea = n∑ EB ( substraty ) −m∑ EB ( produkty )
Która metoda obliczeń daje dokładniejsze rezultaty?
36. Obliczenia ciepła reakcji z energii
wiązań
Przykład 4
Na podstawie wartości energii wiązań z Tabeli
oszacuj ciepło reakcji w 25oC:
∆H = ( 4 EC − H + 2 EO =O ) − ( 2 EC =O + 4 EO − H )
∆H = ( 4 ⋅ 414 + 2 ⋅ 298) − ( 2 ⋅ 741 + 4 ⋅ 464 )
kJ
∆H = −686
mol