1. Electrolyte solutions conduct electricity due to the presence of ions. Strong electrolytes fully dissociate into ions in solution, while weak electrolytes only partially dissociate.
2. Ion transport in electrolyte solutions occurs through diffusion due to concentration gradients and migration due to applied electric fields. Conductivity and molar conductivity describe how well solutions conduct, and depend on factors like ion type and concentration.
3. At infinite dilution, the limiting molar conductivity of electrolytes can be calculated from the ion mobilities. For concentrated solutions, effects like ion-ion interactions cause conductivity to decrease with concentration.
Beaker A contained 0.74 g Ca(OH)2 in 100 ml water. This amount is less than the saturation point of 0.0814 g/100 ml. So the solution was unsaturated.
Beaker B contained 1.48 g Ca(OH)2 in 100 ml water. This amount exceeds the saturation point. So the solution was saturated.
The conductivity and pH would be higher in the saturated solution in Beaker B compared to the unsaturated solution in Beaker A. This is because in a saturated solution, more Ca2+ and OH- ions are available to carry current and increase pH respectively.
So the solution in Beaker B would be more conductive and have a higher pH value than
This document provides information on various topics in electrochemistry. It defines electrolytes and non-electrolytes, and discusses different types of conductors. It also explains electrochemical cells and electrolytic cells. Key concepts covered include electrode potential, the electrochemical series, Faraday's laws of electrolysis, and different types of batteries.
This document provides an overview of electrochemistry concepts including resistance, conductance, conductivity, cell constant, molar conductivity, and their relationships. It discusses how these properties are affected by factors like electrolyte type, concentration, and temperature. Numerical problems demonstrate calculations of conductance, conductivity, and molar conductivity. The variation of molar conductivity with concentration is explained by the Debye-Huckel-Onsager equation and Kohlrausch's law of independent migration of ions. Limiting molar conductivity and its applications are also summarized.
Electrochemistry involves the study of electricity produced from spontaneous chemical reactions in galvanic cells and the use of electricity to drive non-spontaneous reactions in electrolytic cells. Galvanic cells produce electricity through spontaneous redox reactions, with oxidation occurring at the anode and reduction at the cathode. Electrolytic cells use electricity to carry out non-spontaneous reactions. The potential difference between electrodes in a galvanic cell is called the cell potential, which can be calculated using standard electrode potentials and concentrations based on the Nernst equation.
This document discusses conductometry, which is a method of analysis based on measuring the electrolytic conductance of a solution. It begins by classifying different electrochemical methods, including conductometry and electrophoresis which do not involve redox reactions. It then discusses key concepts in conductometry such as conductivity, conductance, equivalent conductance, and how various factors like ion nature, temperature, concentration, and electrode size affect conductance. It also provides examples of calculating conductance and equivalent conductance from experimental measurements. Instrumentation for conductometric determination includes a conductance cell and conductivity bridge.
This document contains a chemistry exam for Class XII with 24 questions testing various concepts. It includes multiple choice questions, very short answer questions, short answer questions, and long answer questions testing topics like electrochemistry, kinetics, properties of elements and ions, and redox reactions. The exam has a total mark of 30 and a duration of 90 minutes.
Beaker A contained 0.74 g Ca(OH)2 in 100 ml water. This amount is less than the saturation point of 0.0814 g/100 ml. So the solution was unsaturated.
Beaker B contained 1.48 g Ca(OH)2 in 100 ml water. This amount exceeds the saturation point. So the solution was saturated.
The conductivity and pH would be higher in the saturated solution in Beaker B compared to the unsaturated solution in Beaker A. This is because in a saturated solution, more Ca2+ and OH- ions are available to carry current and increase pH respectively.
So the solution in Beaker B would be more conductive and have a higher pH value than
This document provides information on various topics in electrochemistry. It defines electrolytes and non-electrolytes, and discusses different types of conductors. It also explains electrochemical cells and electrolytic cells. Key concepts covered include electrode potential, the electrochemical series, Faraday's laws of electrolysis, and different types of batteries.
This document provides an overview of electrochemistry concepts including resistance, conductance, conductivity, cell constant, molar conductivity, and their relationships. It discusses how these properties are affected by factors like electrolyte type, concentration, and temperature. Numerical problems demonstrate calculations of conductance, conductivity, and molar conductivity. The variation of molar conductivity with concentration is explained by the Debye-Huckel-Onsager equation and Kohlrausch's law of independent migration of ions. Limiting molar conductivity and its applications are also summarized.
Electrochemistry involves the study of electricity produced from spontaneous chemical reactions in galvanic cells and the use of electricity to drive non-spontaneous reactions in electrolytic cells. Galvanic cells produce electricity through spontaneous redox reactions, with oxidation occurring at the anode and reduction at the cathode. Electrolytic cells use electricity to carry out non-spontaneous reactions. The potential difference between electrodes in a galvanic cell is called the cell potential, which can be calculated using standard electrode potentials and concentrations based on the Nernst equation.
This document discusses conductometry, which is a method of analysis based on measuring the electrolytic conductance of a solution. It begins by classifying different electrochemical methods, including conductometry and electrophoresis which do not involve redox reactions. It then discusses key concepts in conductometry such as conductivity, conductance, equivalent conductance, and how various factors like ion nature, temperature, concentration, and electrode size affect conductance. It also provides examples of calculating conductance and equivalent conductance from experimental measurements. Instrumentation for conductometric determination includes a conductance cell and conductivity bridge.
This document contains a chemistry exam for Class XII with 24 questions testing various concepts. It includes multiple choice questions, very short answer questions, short answer questions, and long answer questions testing topics like electrochemistry, kinetics, properties of elements and ions, and redox reactions. The exam has a total mark of 30 and a duration of 90 minutes.
Postsecondary lesson for pre-u students or form 6th students on mole concept, stoichiometry, limiting reagent, spectrometry and percent yield and percent purity.
This document provides an overview of electrochemistry and electrolytic cells. It discusses:
- Electrochemistry involves the study of redox reactions and the transfer of electrons, including oxidation which is the loss of electrons and reduction which is the gain of electrons.
- Electrolytic cells use electrical energy to drive redox reactions in a direction that does not occur spontaneously, with examples of cathode and anode half reactions.
- Quantitative electrolysis allows control over the amount of substance undergoing a reaction, according to Faraday's laws - the amount of reaction is proportional to the charge passed, and different electrolytes require different amounts of electrons for the same reaction.
- An example problem calculates the mass of copper
1) Electrochemistry deals with interconversion of electrical and chemical energy. In batteries, chemical energy is converted to electrical energy, while in electrolysis and electroplating, electrical energy is converted to chemical energy.
2) Conductors allow electric current to pass through them. Metallic conductors conduct via electrons, while electrolytic conductors conduct via ions when in solution or molten state.
3) Concentration cells produce electrical energy from differences in concentration of electrolytes or electrodes in two half-cells, without an overall chemical reaction. The cell potential can be calculated from Nernst's equation and depends on the log of the concentration ratio.
This document discusses electrochemistry and key concepts related to conductivity of electrolyte solutions. It defines electrochemistry as the study of chemical reactions caused by electricity or electrical energy and the conversion between chemical and electrical energy. It describes how conductivity is measured and how it varies with concentration, temperature, and other factors for strong and weak electrolytes. The document also discusses concepts such as molar conductivity, transport numbers, solubility products, and the Debye-Hückel theory of ionic interactions.
This document provides an overview of basic chemistry concepts including:
- The law of multiple proportions and how it is illustrated by nitrogen and hydrogen oxides.
- Definitions of a mole and how it is used to calculate the number of hydrogen atoms in 1 mole of methane.
- How stoichiometry is used to calculate the amount of water formed from the combustion of a given amount of methane.
- The concept of a limiting reagent and how to calculate the mass of a product given specific amounts of reactants.
- A summary of the key observations and conclusions from Rutherford's gold foil experiment that led to the nuclear model of the atom.
This document provides an overview of basic electrochemistry concepts. It discusses the charge and current involved in electrochemical processes. It introduces Faraday's laws relating the amount of material transformed to the quantity of electricity passed. It also covers conductivity, Nernst equation, different types of electrodes, potentiometry, and various electrochemical techniques including cyclic voltammetry. The key concepts covered include electron transfer processes, Butler-Volmer equation, mass transport by diffusion and convection, and reversible cyclic voltammograms.
Introduction
Ohm’s law.
Conductometric measurements.
Factor affecting conductivity.
Application of conductometry.
2.Conductometric titration-:
Introduction.
Types of conductometric tiration.
Advantages of conductometric tiration.
3.Recent devlopement
Conductometry:
is the simplest of the electroanalytical techniques; by Kolthoff in 1929.
Conductors are:
either metallic (flow of electrons) or electrolytic (movemenmt of ions).
Conductance of electricity:
migration of positively charged ions towards the cathode and negatively charged ones towards the anode
(i.e.) current is carried by all ions present in solution.
Conductance depends on the number of ions in solun.
Factors affecting conductance:
1- Temperature:
(1C increase in temperature causes 2 % increase in conductance).
2- Nature of ions
Size, molecular weight and number of charges.
3- Concentration of ions:
As the number of ions increases, the conductance increases.
4- Size of electrodes
Conductance is directly proportional to the cross sectional area (A).
This document discusses oxidation-reduction (redox) reactions and electrochemistry.
1. It explains how to identify redox reactions by checking if the oxidation number (O.N.) of any species changes in the reaction. An example reaction between permanganate and oxalic acid is given.
2. Balancing redox reactions is important, and the document outlines the step-by-step process for balancing both acidic and basic redox reactions.
3. Electrochemical cells are described as either galvanic cells that generate potential or electrolytic cells that consume potential. The standard hydrogen electrode is used as a reference electrode with a standard potential of 0 V.
1. Electrochemistry deals with the production of electricity from chemical reactions and use of electricity to cause non-spontaneous reactions.
2. Conductors are classified as metallic conductors which allow current by electron movement and electrolytic conductors which allow current through dissolved or molten state with chemical decomposition.
3. Electrolytes are classified as strong which completely dissociate and weak which partially dissociate. Conductivity is directly proportional to concentration and inversely proportional to length.
This document provides information on electrochemistry and electrochemical cells. It defines electrochemistry as the study of electricity production from spontaneous chemical reactions and use of electrical energy for non-spontaneous reactions. It describes different types of electrochemical cells including galvanic cells that convert chemical to electrical energy and electrolytic cells that do the opposite. Key concepts discussed include electrode potentials, standard hydrogen electrode, Nernst equation, and factors affecting cell potential. Common electrochemical devices like batteries and the corrosion process are also summarized.
Conductance of electrolyte solution, specific, equivalent and molar conductance. Determination conductance of electrolyte solution, Cell constant its determination and problems
This document discusses conductimetric techniques, which involve measuring the electrical conductivity of a solution to determine the concentration of ionic species. Conductivity is measured using a conductimeter, which applies an electric field between electrodes in a conductivity cell and measures the solution's resistance. Factors that affect conductivity include temperature, ion type and concentration, and electrode properties. Common applications of conductimetry include water purity testing and ion chromatography detection.
This document discusses electrolytic cells and electrolysis. It defines electrolytic cells as cells that convert electrical energy to chemical energy through electrolysis. Electrolysis is the process of using an electric current to drive non-spontaneous redox reactions through an electrolyte. The document then discusses different types of electrolytic cells like those using molten NaCl or aqueous NaCl solutions. It also covers quantitative calculations related to electrolysis like determining moles of electrons passed or mass of products formed. Finally, it briefly discusses connecting two electrolytic cells in series and the function of a salt bridge.
This document provides an overview of electrochemistry concepts including:
(1) Electrolytes are substances that conduct electricity in solution via ion movement, while non-electrolytes do not conduct. Examples of each are given.
(2) Strong and weak electrolytes are described based on their degree of ionization. Common examples of each type are listed.
(3) Key differences between electronic and electrolytic conductors are outlined regarding how electricity flows through each type.
1. Electrolytes are substances that dissociate into ions when dissolved in water, allowing them to conduct electricity. They can be classified as strong, weak, or non-electrolytes based on their conductivity.
2. Electrodes are materials inserted into electrolytic cells, and are classified as anodes or cathodes depending on whether oxidation or reduction occurs. During electrolysis, ions migrate to electrodes and undergo chemical reactions.
3. Faraday's laws of electrolysis describe the relationships between electrical charge passed, mass of substance deposited, current over time, and equivalent weights of elements involved in electrolysis reactions.
B.tech. ii engineering chemistry unit 5 A electrochemistryRai University
Arrhenius proposed the theory of electrolytic dissociation to explain the properties of electrolytic solutions. The theory states that when an electrolyte dissolves in water, it breaks up into ions - positively charged cations and negatively charged anions. This process is called ionization. Ions are constantly recombining and dissociating, reaching a state of dynamic equilibrium. The extent of ionization depends on an equilibrium constant. Strong electrolytes have a high equilibrium constant and ionize completely, while weak electrolytes have a low constant and only partially ionize.
1) Electrons in atoms can only exist at certain discrete energy levels called quantum states. This is because electrons behave like waves and their wavelengths must fit within the boundaries of the atom.
2) Niels Bohr used this idea to explain the emission spectrum of hydrogen, showing electrons jumping between allowed orbits.
3) Later, the de Broglie hypothesis established that all particles like electrons exhibit both wave and particle properties. Treating electrons as waves led to the modern quantum mechanical model of atomic structure.
The document provides an overview of several instrumental techniques used for structure determination of organic compounds, including mass spectrometry, infrared spectroscopy, UV-visible spectroscopy, nuclear magnetic resonance spectroscopy, and gas chromatography-mass spectrometry. It discusses sample preparation, basic principles, and how to interpret data from each technique.
The document describes calculating the cell potential of a galvanic cell made by coupling a standard Zn/Zn2+ electrode to a standard hydrogen electrode at 25°C, where the hydrogen electrode is buffered to pH=5.57. Using the Nernst equation, the resulting cell potential is calculated to be 0.434 V.
Microbial interaction
Microorganisms interacts with each other and can be physically associated with another organisms in a variety of ways.
One organism can be located on the surface of another organism as an ectobiont or located within another organism as endobiont.
Microbial interaction may be positive such as mutualism, proto-cooperation, commensalism or may be negative such as parasitism, predation or competition
Types of microbial interaction
Positive interaction: mutualism, proto-cooperation, commensalism
Negative interaction: Ammensalism (antagonism), parasitism, predation, competition
I. Mutualism:
It is defined as the relationship in which each organism in interaction gets benefits from association. It is an obligatory relationship in which mutualist and host are metabolically dependent on each other.
Mutualistic relationship is very specific where one member of association cannot be replaced by another species.
Mutualism require close physical contact between interacting organisms.
Relationship of mutualism allows organisms to exist in habitat that could not occupied by either species alone.
Mutualistic relationship between organisms allows them to act as a single organism.
Examples of mutualism:
i. Lichens:
Lichens are excellent example of mutualism.
They are the association of specific fungi and certain genus of algae. In lichen, fungal partner is called mycobiont and algal partner is called
II. Syntrophism:
It is an association in which the growth of one organism either depends on or improved by the substrate provided by another organism.
In syntrophism both organism in association gets benefits.
Compound A
Utilized by population 1
Compound B
Utilized by population 2
Compound C
utilized by both Population 1+2
Products
In this theoretical example of syntrophism, population 1 is able to utilize and metabolize compound A, forming compound B but cannot metabolize beyond compound B without co-operation of population 2. Population 2is unable to utilize compound A but it can metabolize compound B forming compound C. Then both population 1 and 2 are able to carry out metabolic reaction which leads to formation of end product that neither population could produce alone.
Examples of syntrophism:
i. Methanogenic ecosystem in sludge digester
Methane produced by methanogenic bacteria depends upon interspecies hydrogen transfer by other fermentative bacteria.
Anaerobic fermentative bacteria generate CO2 and H2 utilizing carbohydrates which is then utilized by methanogenic bacteria (Methanobacter) to produce methane.
ii. Lactobacillus arobinosus and Enterococcus faecalis:
In the minimal media, Lactobacillus arobinosus and Enterococcus faecalis are able to grow together but not alone.
The synergistic relationship between E. faecalis and L. arobinosus occurs in which E. faecalis require folic acid
CLASS 12th CHEMISTRY SOLID STATE ppt (Animated)eitps1506
Description:
Dive into the fascinating realm of solid-state physics with our meticulously crafted online PowerPoint presentation. This immersive educational resource offers a comprehensive exploration of the fundamental concepts, theories, and applications within the realm of solid-state physics.
From crystalline structures to semiconductor devices, this presentation delves into the intricate principles governing the behavior of solids, providing clear explanations and illustrative examples to enhance understanding. Whether you're a student delving into the subject for the first time or a seasoned researcher seeking to deepen your knowledge, our presentation offers valuable insights and in-depth analyses to cater to various levels of expertise.
Key topics covered include:
Crystal Structures: Unravel the mysteries of crystalline arrangements and their significance in determining material properties.
Band Theory: Explore the electronic band structure of solids and understand how it influences their conductive properties.
Semiconductor Physics: Delve into the behavior of semiconductors, including doping, carrier transport, and device applications.
Magnetic Properties: Investigate the magnetic behavior of solids, including ferromagnetism, antiferromagnetism, and ferrimagnetism.
Optical Properties: Examine the interaction of light with solids, including absorption, reflection, and transmission phenomena.
With visually engaging slides, informative content, and interactive elements, our online PowerPoint presentation serves as a valuable resource for students, educators, and enthusiasts alike, facilitating a deeper understanding of the captivating world of solid-state physics. Explore the intricacies of solid-state materials and unlock the secrets behind their remarkable properties with our comprehensive presentation.
PPT on Alternate Wetting and Drying presented at the three-day 'Training and Validation Workshop on Modules of Climate Smart Agriculture (CSA) Technologies in South Asia' workshop on April 22, 2024.
Postsecondary lesson for pre-u students or form 6th students on mole concept, stoichiometry, limiting reagent, spectrometry and percent yield and percent purity.
This document provides an overview of electrochemistry and electrolytic cells. It discusses:
- Electrochemistry involves the study of redox reactions and the transfer of electrons, including oxidation which is the loss of electrons and reduction which is the gain of electrons.
- Electrolytic cells use electrical energy to drive redox reactions in a direction that does not occur spontaneously, with examples of cathode and anode half reactions.
- Quantitative electrolysis allows control over the amount of substance undergoing a reaction, according to Faraday's laws - the amount of reaction is proportional to the charge passed, and different electrolytes require different amounts of electrons for the same reaction.
- An example problem calculates the mass of copper
1) Electrochemistry deals with interconversion of electrical and chemical energy. In batteries, chemical energy is converted to electrical energy, while in electrolysis and electroplating, electrical energy is converted to chemical energy.
2) Conductors allow electric current to pass through them. Metallic conductors conduct via electrons, while electrolytic conductors conduct via ions when in solution or molten state.
3) Concentration cells produce electrical energy from differences in concentration of electrolytes or electrodes in two half-cells, without an overall chemical reaction. The cell potential can be calculated from Nernst's equation and depends on the log of the concentration ratio.
This document discusses electrochemistry and key concepts related to conductivity of electrolyte solutions. It defines electrochemistry as the study of chemical reactions caused by electricity or electrical energy and the conversion between chemical and electrical energy. It describes how conductivity is measured and how it varies with concentration, temperature, and other factors for strong and weak electrolytes. The document also discusses concepts such as molar conductivity, transport numbers, solubility products, and the Debye-Hückel theory of ionic interactions.
This document provides an overview of basic chemistry concepts including:
- The law of multiple proportions and how it is illustrated by nitrogen and hydrogen oxides.
- Definitions of a mole and how it is used to calculate the number of hydrogen atoms in 1 mole of methane.
- How stoichiometry is used to calculate the amount of water formed from the combustion of a given amount of methane.
- The concept of a limiting reagent and how to calculate the mass of a product given specific amounts of reactants.
- A summary of the key observations and conclusions from Rutherford's gold foil experiment that led to the nuclear model of the atom.
This document provides an overview of basic electrochemistry concepts. It discusses the charge and current involved in electrochemical processes. It introduces Faraday's laws relating the amount of material transformed to the quantity of electricity passed. It also covers conductivity, Nernst equation, different types of electrodes, potentiometry, and various electrochemical techniques including cyclic voltammetry. The key concepts covered include electron transfer processes, Butler-Volmer equation, mass transport by diffusion and convection, and reversible cyclic voltammograms.
Introduction
Ohm’s law.
Conductometric measurements.
Factor affecting conductivity.
Application of conductometry.
2.Conductometric titration-:
Introduction.
Types of conductometric tiration.
Advantages of conductometric tiration.
3.Recent devlopement
Conductometry:
is the simplest of the electroanalytical techniques; by Kolthoff in 1929.
Conductors are:
either metallic (flow of electrons) or electrolytic (movemenmt of ions).
Conductance of electricity:
migration of positively charged ions towards the cathode and negatively charged ones towards the anode
(i.e.) current is carried by all ions present in solution.
Conductance depends on the number of ions in solun.
Factors affecting conductance:
1- Temperature:
(1C increase in temperature causes 2 % increase in conductance).
2- Nature of ions
Size, molecular weight and number of charges.
3- Concentration of ions:
As the number of ions increases, the conductance increases.
4- Size of electrodes
Conductance is directly proportional to the cross sectional area (A).
This document discusses oxidation-reduction (redox) reactions and electrochemistry.
1. It explains how to identify redox reactions by checking if the oxidation number (O.N.) of any species changes in the reaction. An example reaction between permanganate and oxalic acid is given.
2. Balancing redox reactions is important, and the document outlines the step-by-step process for balancing both acidic and basic redox reactions.
3. Electrochemical cells are described as either galvanic cells that generate potential or electrolytic cells that consume potential. The standard hydrogen electrode is used as a reference electrode with a standard potential of 0 V.
1. Electrochemistry deals with the production of electricity from chemical reactions and use of electricity to cause non-spontaneous reactions.
2. Conductors are classified as metallic conductors which allow current by electron movement and electrolytic conductors which allow current through dissolved or molten state with chemical decomposition.
3. Electrolytes are classified as strong which completely dissociate and weak which partially dissociate. Conductivity is directly proportional to concentration and inversely proportional to length.
This document provides information on electrochemistry and electrochemical cells. It defines electrochemistry as the study of electricity production from spontaneous chemical reactions and use of electrical energy for non-spontaneous reactions. It describes different types of electrochemical cells including galvanic cells that convert chemical to electrical energy and electrolytic cells that do the opposite. Key concepts discussed include electrode potentials, standard hydrogen electrode, Nernst equation, and factors affecting cell potential. Common electrochemical devices like batteries and the corrosion process are also summarized.
Conductance of electrolyte solution, specific, equivalent and molar conductance. Determination conductance of electrolyte solution, Cell constant its determination and problems
This document discusses conductimetric techniques, which involve measuring the electrical conductivity of a solution to determine the concentration of ionic species. Conductivity is measured using a conductimeter, which applies an electric field between electrodes in a conductivity cell and measures the solution's resistance. Factors that affect conductivity include temperature, ion type and concentration, and electrode properties. Common applications of conductimetry include water purity testing and ion chromatography detection.
This document discusses electrolytic cells and electrolysis. It defines electrolytic cells as cells that convert electrical energy to chemical energy through electrolysis. Electrolysis is the process of using an electric current to drive non-spontaneous redox reactions through an electrolyte. The document then discusses different types of electrolytic cells like those using molten NaCl or aqueous NaCl solutions. It also covers quantitative calculations related to electrolysis like determining moles of electrons passed or mass of products formed. Finally, it briefly discusses connecting two electrolytic cells in series and the function of a salt bridge.
This document provides an overview of electrochemistry concepts including:
(1) Electrolytes are substances that conduct electricity in solution via ion movement, while non-electrolytes do not conduct. Examples of each are given.
(2) Strong and weak electrolytes are described based on their degree of ionization. Common examples of each type are listed.
(3) Key differences between electronic and electrolytic conductors are outlined regarding how electricity flows through each type.
1. Electrolytes are substances that dissociate into ions when dissolved in water, allowing them to conduct electricity. They can be classified as strong, weak, or non-electrolytes based on their conductivity.
2. Electrodes are materials inserted into electrolytic cells, and are classified as anodes or cathodes depending on whether oxidation or reduction occurs. During electrolysis, ions migrate to electrodes and undergo chemical reactions.
3. Faraday's laws of electrolysis describe the relationships between electrical charge passed, mass of substance deposited, current over time, and equivalent weights of elements involved in electrolysis reactions.
B.tech. ii engineering chemistry unit 5 A electrochemistryRai University
Arrhenius proposed the theory of electrolytic dissociation to explain the properties of electrolytic solutions. The theory states that when an electrolyte dissolves in water, it breaks up into ions - positively charged cations and negatively charged anions. This process is called ionization. Ions are constantly recombining and dissociating, reaching a state of dynamic equilibrium. The extent of ionization depends on an equilibrium constant. Strong electrolytes have a high equilibrium constant and ionize completely, while weak electrolytes have a low constant and only partially ionize.
1) Electrons in atoms can only exist at certain discrete energy levels called quantum states. This is because electrons behave like waves and their wavelengths must fit within the boundaries of the atom.
2) Niels Bohr used this idea to explain the emission spectrum of hydrogen, showing electrons jumping between allowed orbits.
3) Later, the de Broglie hypothesis established that all particles like electrons exhibit both wave and particle properties. Treating electrons as waves led to the modern quantum mechanical model of atomic structure.
The document provides an overview of several instrumental techniques used for structure determination of organic compounds, including mass spectrometry, infrared spectroscopy, UV-visible spectroscopy, nuclear magnetic resonance spectroscopy, and gas chromatography-mass spectrometry. It discusses sample preparation, basic principles, and how to interpret data from each technique.
The document describes calculating the cell potential of a galvanic cell made by coupling a standard Zn/Zn2+ electrode to a standard hydrogen electrode at 25°C, where the hydrogen electrode is buffered to pH=5.57. Using the Nernst equation, the resulting cell potential is calculated to be 0.434 V.
Microbial interaction
Microorganisms interacts with each other and can be physically associated with another organisms in a variety of ways.
One organism can be located on the surface of another organism as an ectobiont or located within another organism as endobiont.
Microbial interaction may be positive such as mutualism, proto-cooperation, commensalism or may be negative such as parasitism, predation or competition
Types of microbial interaction
Positive interaction: mutualism, proto-cooperation, commensalism
Negative interaction: Ammensalism (antagonism), parasitism, predation, competition
I. Mutualism:
It is defined as the relationship in which each organism in interaction gets benefits from association. It is an obligatory relationship in which mutualist and host are metabolically dependent on each other.
Mutualistic relationship is very specific where one member of association cannot be replaced by another species.
Mutualism require close physical contact between interacting organisms.
Relationship of mutualism allows organisms to exist in habitat that could not occupied by either species alone.
Mutualistic relationship between organisms allows them to act as a single organism.
Examples of mutualism:
i. Lichens:
Lichens are excellent example of mutualism.
They are the association of specific fungi and certain genus of algae. In lichen, fungal partner is called mycobiont and algal partner is called
II. Syntrophism:
It is an association in which the growth of one organism either depends on or improved by the substrate provided by another organism.
In syntrophism both organism in association gets benefits.
Compound A
Utilized by population 1
Compound B
Utilized by population 2
Compound C
utilized by both Population 1+2
Products
In this theoretical example of syntrophism, population 1 is able to utilize and metabolize compound A, forming compound B but cannot metabolize beyond compound B without co-operation of population 2. Population 2is unable to utilize compound A but it can metabolize compound B forming compound C. Then both population 1 and 2 are able to carry out metabolic reaction which leads to formation of end product that neither population could produce alone.
Examples of syntrophism:
i. Methanogenic ecosystem in sludge digester
Methane produced by methanogenic bacteria depends upon interspecies hydrogen transfer by other fermentative bacteria.
Anaerobic fermentative bacteria generate CO2 and H2 utilizing carbohydrates which is then utilized by methanogenic bacteria (Methanobacter) to produce methane.
ii. Lactobacillus arobinosus and Enterococcus faecalis:
In the minimal media, Lactobacillus arobinosus and Enterococcus faecalis are able to grow together but not alone.
The synergistic relationship between E. faecalis and L. arobinosus occurs in which E. faecalis require folic acid
CLASS 12th CHEMISTRY SOLID STATE ppt (Animated)eitps1506
Description:
Dive into the fascinating realm of solid-state physics with our meticulously crafted online PowerPoint presentation. This immersive educational resource offers a comprehensive exploration of the fundamental concepts, theories, and applications within the realm of solid-state physics.
From crystalline structures to semiconductor devices, this presentation delves into the intricate principles governing the behavior of solids, providing clear explanations and illustrative examples to enhance understanding. Whether you're a student delving into the subject for the first time or a seasoned researcher seeking to deepen your knowledge, our presentation offers valuable insights and in-depth analyses to cater to various levels of expertise.
Key topics covered include:
Crystal Structures: Unravel the mysteries of crystalline arrangements and their significance in determining material properties.
Band Theory: Explore the electronic band structure of solids and understand how it influences their conductive properties.
Semiconductor Physics: Delve into the behavior of semiconductors, including doping, carrier transport, and device applications.
Magnetic Properties: Investigate the magnetic behavior of solids, including ferromagnetism, antiferromagnetism, and ferrimagnetism.
Optical Properties: Examine the interaction of light with solids, including absorption, reflection, and transmission phenomena.
With visually engaging slides, informative content, and interactive elements, our online PowerPoint presentation serves as a valuable resource for students, educators, and enthusiasts alike, facilitating a deeper understanding of the captivating world of solid-state physics. Explore the intricacies of solid-state materials and unlock the secrets behind their remarkable properties with our comprehensive presentation.
PPT on Alternate Wetting and Drying presented at the three-day 'Training and Validation Workshop on Modules of Climate Smart Agriculture (CSA) Technologies in South Asia' workshop on April 22, 2024.
Discovery of An Apparent Red, High-Velocity Type Ia Supernova at 𝐳 = 2.9 wi...Sérgio Sacani
We present the JWST discovery of SN 2023adsy, a transient object located in a host galaxy JADES-GS
+
53.13485
−
27.82088
with a host spectroscopic redshift of
2.903
±
0.007
. The transient was identified in deep James Webb Space Telescope (JWST)/NIRCam imaging from the JWST Advanced Deep Extragalactic Survey (JADES) program. Photometric and spectroscopic followup with NIRCam and NIRSpec, respectively, confirm the redshift and yield UV-NIR light-curve, NIR color, and spectroscopic information all consistent with a Type Ia classification. Despite its classification as a likely SN Ia, SN 2023adsy is both fairly red (
�
(
�
−
�
)
∼
0.9
) despite a host galaxy with low-extinction and has a high Ca II velocity (
19
,
000
±
2
,
000
km/s) compared to the general population of SNe Ia. While these characteristics are consistent with some Ca-rich SNe Ia, particularly SN 2016hnk, SN 2023adsy is intrinsically brighter than the low-
�
Ca-rich population. Although such an object is too red for any low-
�
cosmological sample, we apply a fiducial standardization approach to SN 2023adsy and find that the SN 2023adsy luminosity distance measurement is in excellent agreement (
≲
1
�
) with
Λ
CDM. Therefore unlike low-
�
Ca-rich SNe Ia, SN 2023adsy is standardizable and gives no indication that SN Ia standardized luminosities change significantly with redshift. A larger sample of distant SNe Ia is required to determine if SN Ia population characteristics at high-
�
truly diverge from their low-
�
counterparts, and to confirm that standardized luminosities nevertheless remain constant with redshift.
Mending Clothing to Support Sustainable Fashion_CIMaR 2024.pdfSelcen Ozturkcan
Ozturkcan, S., Berndt, A., & Angelakis, A. (2024). Mending clothing to support sustainable fashion. Presented at the 31st Annual Conference by the Consortium for International Marketing Research (CIMaR), 10-13 Jun 2024, University of Gävle, Sweden.
Authoring a personal GPT for your research and practice: How we created the Q...Leonel Morgado
Thematic analysis in qualitative research is a time-consuming and systematic task, typically done using teams. Team members must ground their activities on common understandings of the major concepts underlying the thematic analysis, and define criteria for its development. However, conceptual misunderstandings, equivocations, and lack of adherence to criteria are challenges to the quality and speed of this process. Given the distributed and uncertain nature of this process, we wondered if the tasks in thematic analysis could be supported by readily available artificial intelligence chatbots. Our early efforts point to potential benefits: not just saving time in the coding process but better adherence to criteria and grounding, by increasing triangulation between humans and artificial intelligence. This tutorial will provide a description and demonstration of the process we followed, as two academic researchers, to develop a custom ChatGPT to assist with qualitative coding in the thematic data analysis process of immersive learning accounts in a survey of the academic literature: QUAL-E Immersive Learning Thematic Analysis Helper. In the hands-on time, participants will try out QUAL-E and develop their ideas for their own qualitative coding ChatGPT. Participants that have the paid ChatGPT Plus subscription can create a draft of their assistants. The organizers will provide course materials and slide deck that participants will be able to utilize to continue development of their custom GPT. The paid subscription to ChatGPT Plus is not required to participate in this workshop, just for trying out personal GPTs during it.
PPT on Direct Seeded Rice presented at the three-day 'Training and Validation Workshop on Modules of Climate Smart Agriculture (CSA) Technologies in South Asia' workshop on April 22, 2024.
Anti-Universe And Emergent Gravity and the Dark UniverseSérgio Sacani
Recent theoretical progress indicates that spacetime and gravity emerge together from the entanglement structure of an underlying microscopic theory. These ideas are best understood in Anti-de Sitter space, where they rely on the area law for entanglement entropy. The extension to de Sitter space requires taking into account the entropy and temperature associated with the cosmological horizon. Using insights from string theory, black hole physics and quantum information theory we argue that the positive dark energy leads to a thermal volume law contribution to the entropy that overtakes the area law precisely at the cosmological horizon. Due to the competition between area and volume law entanglement the microscopic de Sitter states do not thermalise at sub-Hubble scales: they exhibit memory effects in the form of an entropy displacement caused by matter. The emergent laws of gravity contain an additional ‘dark’ gravitational force describing the ‘elastic’ response due to the entropy displacement. We derive an estimate of the strength of this extra force in terms of the baryonic mass, Newton’s constant and the Hubble acceleration scale a0 = cH0, and provide evidence for the fact that this additional ‘dark gravity force’ explains the observed phenomena in galaxies and clusters currently attributed to dark matter.
JAMES WEBB STUDY THE MASSIVE BLACK HOLE SEEDSSérgio Sacani
The pathway(s) to seeding the massive black holes (MBHs) that exist at the heart of galaxies in the present and distant Universe remains an unsolved problem. Here we categorise, describe and quantitatively discuss the formation pathways of both light and heavy seeds. We emphasise that the most recent computational models suggest that rather than a bimodal-like mass spectrum between light and heavy seeds with light at one end and heavy at the other that instead a continuum exists. Light seeds being more ubiquitous and the heavier seeds becoming less and less abundant due the rarer environmental conditions required for their formation. We therefore examine the different mechanisms that give rise to different seed mass spectrums. We show how and why the mechanisms that produce the heaviest seeds are also among the rarest events in the Universe and are hence extremely unlikely to be the seeds for the vast majority of the MBH population. We quantify, within the limits of the current large uncertainties in the seeding processes, the expected number densities of the seed mass spectrum. We argue that light seeds must be at least 103 to 105 times more numerous than heavy seeds to explain the MBH population as a whole. Based on our current understanding of the seed population this makes heavy seeds (Mseed > 103 M⊙) a significantly more likely pathway given that heavy seeds have an abundance pattern than is close to and likely in excess of 10−4 compared to light seeds. Finally, we examine the current state-of-the-art in numerical calculations and recent observations and plot a path forward for near-future advances in both domains.
2. 1.1 Introduction
Electrolytic solutions: Solutions which conduct electricity.
Types of electrolytes
a) True Electrolytes: Composed of ions in pure state.
E.g. NaCl
b) Potential Electrolytes: Form ions in solutions.
consist of uncharged molecules in the pure state.
E.g. 1. HCl – strong electrolyte
HCl + H2O H3O+ + Cl- (aq)
E.g. 2. CH3COOH – weak electrolyte
2
CH3COOH + H2O CH3COO-
+ H3O+
3. 1.2. Transport Properties
Ions move in electrolyte solutions between anode and cathode.
Solvated ions move at different velocities, depending on their size
and charge.
The movement is of two types.
a) Diffusion: Movement of ions due to concentration gradient.
b) Migration: Movement of ions due to electric field which is
applied between two electrodes immersed in an electrolyte
solution.
Diffusion is described by Fick’s first law.
𝐉i = −𝐃
𝝏𝑪i
𝝏𝒙
Where Ji = flux of species i of concentration Ci in the x-direction,
𝜕𝐶i
𝜕𝑥
= Concentration gradient of i, D = Diffusion coefficient of i
3
4. In the presence of an applied electric field, the flux of ions is
described by:
𝐉i = −𝐃
𝝏𝑪i
𝝏𝒙
− 𝒁i𝑪i
𝑭
𝑹𝑻
𝑬
Where the second term is due to migration effect.
1.2.1. Conductance and Conductivity
a) Conductance (G): The conductance of a solution is the inverse of
its resistance.
𝑮 =
𝟏
𝑹
Unit: Siemens (S). 1S = 1 -1 = 1CV-1s-1
The resistance of a sample increases with its length (l) and
decreases with its cross-sectional area (A).
Hence,
𝑮 =
𝑨
𝒍
Where = conductivity
4
5. b) Conductivity (): It is described by the equation:
= 𝑮
𝒍
𝑨
Unit: Sm-1
The conductivity of a sample is measured in a conductivity cell.
𝑙
𝐴
= 𝑐𝑒𝑙𝑙 𝑐𝑜𝑛𝑠𝑡𝑎𝑛𝑡
= cell constant G = cell constant/R
The conductivity of a solution depends on the number of ions
present.
c) Molar conductivity (m): It is the conductivity of a solution which
contains one molar of the electrolyte.
m =
𝒄
where c = molar concentration of the electrolyte.
5
6. Unit: Sm2mol-1
Range: 10-2Sm2mol-1
E.g.
The resistance of a conductivity cell filled with 0.01 M KCl solution at
25oC is 747.5 . Its conductivity is 0.14 -1m-1.
If the resistance of a 0.005 M CaCl2 is 876 . Calculate
a) the cell constant b) the conductivity of CaCl2 solution c) the molar
conductivity of the CaCl2 solution.
Solution:
a) Cell constant = R = 0.14-1 m-1 747.5 = 104.6 m-1
b) 𝐶𝑎𝐶𝑙2 =
𝑐𝑒𝑙𝑙 𝑐𝑜𝑛𝑠𝑡𝑎𝑛𝑡
𝑅
=
104.65𝑚−1
876
= 0.11946−1𝑚−1
= 1.1946𝑚𝑆𝑐𝑚−1
c) 0.005M = 0.005 mol dm-3 = 5 mol m-3
m =
𝑐
=
0.11946𝑆𝑚−1
5𝑚𝑜𝑙𝑚−3
= 0.023892𝑆𝑚2𝑚𝑜𝑙−1 = 238.92𝑆𝑐𝑚2𝑚𝑜𝑙−1
6
7. Exercise: The conductivity of a 1.0 mol dm-3 aqueous KCl solution at
25oC is 0.112-1 cm-1.
Find its molar conductivity. (Answer: 112 Scm2 mol-1)
Molar conductivity depends on:
1) Type of solvent - E.g. m (LiCl), (water) > m (LiCl), (propanone)
2) Type of electrolyte – E.g. m (HCl) > m (KCl)
3) Concentration: Molar conductivity is expected to be independent
of concentration.
In reality, as concentration increases:
i. For strong electrolytes: the interaction between ions increases.
Therefore, molar conductivity decreases with increasing
concentration.
7
8. ii. For weak electrolytes: The degree of dissociation decreases.
Therefore, molar conductivity decreases.
d) Limiting Molar Conductivity (o
m)
It is the molar conductivity of a solution at infinite dilution (c 0)
Law of Independent migration of ions:
At infinite dilution, the conductivity of an electrolyte is a result
of the independent contributions of individual ions.
8
CH3COOH
HCl
KCl
C
CH3COOH
KCl
HCl
m
C
9. o
m = ++ + --
where + , - = limiting ionic conductivity of + ve and – ve ions
+, - = number of + ve and – ve ions per formula unit
The law holds for strong electrolytes.
Examples of limiting ionic conductivities:
9
10. Example:
Determine the limiting molar conductivity of Na2SO4.
Solution
o
m = ++ + -- = 2Na
+ + SO4
2- = (25.01 + 116) mSm2mol-1
= 26.02 mSm2mol-1
The law of independent migration of ions is important to
determine the limiting molar conductance of weak electrolytes.
Example:
o
m of NH4Cl, NaCl and NaOH in aqueous solution at 25oC are
0.01497, 0.01265 and 0.02478 Sm2mol-1, respectively. Determine o
m
of NH4OH which is a weak electrolyte.
Solution
o
m (NH4OH) = o
m (NH4Cl) + o
m (NaOH) - o
m (NaCl) = o
m (NH4
+) + o
m (Cl-) + o
m
(Na+) + o
m (OH-) - o
m (Na+) - o
m (Cl-) = o
m (NH4
+) + o
m (OH-)
10
11. Therefore,
o
m (NH4OH) = (0.01497 + 0.02478 - 0.01265) Sm2mol-1 = 0.02710 Sm2mol-1
e) Effect of concentration on molar conductivity
i. For strong electrolytes: At low concentrations, the molar
conductivities of strong electrolytes vary linearly with the square
root of the concentration.
m = o
m − 𝒄½ Kohlrausch’s law
The c½ dependence arises from interactions between ions that
retard the ion’s progress.
ii. For weak electrolytes: The concentration dependence arises from
the decrease in the degree of dissociation () with increasing
concentration due to the displacement of the equilibrium:
11
12. For a weak acid, HA:
𝐾a =
𝐻3𝑂+ 𝐴−
(aq)
[𝐻𝐴]
At equilibrium, [H3O+] = [A-] = c where is the degree of ionization.
[HA] = (1 - ) c
Therefore,
𝐾a =
𝑐22
1− 𝑐
𝐾a =
𝑐2
1−
Rearrangement yields,
1
= 1 +
𝑐
𝐾a
When the degree of dissociation is , m becomes:
m = o
m
Hence,
=
m
o
m
12
H
A + H
2O A
-
+ H
3O+
13. Substituting for yields,
Ostwald dilution law
o
m can be determined by extrapolation to zero concentration in
the plot of 1/m vs. mc.
Example 1: The resistance of a 0.025M HAc measured in a cell (cell
constant = 0.367 cm-1) was found to be 444 . Calculate Ka. (o
m
(HAc ) = 390.7Scm2mol-1)
Solution:
𝐾a =
𝑐2
1−
1dm-3 = 10-3cm-3
13
14. Example 2: The molar conductivity of 0.01 M HAc at 298 K is m =
1.65 mSm2mol-1 and its limiting molar conductivity is 39.05 mSm2mol-
1. Calculate the acidity constant of the acid.
Solution
14
15. 1.2.2. The mobilities of Ions and the Transport Number
These properties help to understand the role of ions in electrical
conduction.
a) Drift speed and Mobility
When the potential difference between two electrodes a distance
l apart is , the ions in the solution between them experience a
uniform electric field of magnitude, E.
An ion of charge Ze experiences a force of magnitude,
15
16. As a result, the cation accelerates towards the negative electrode
and the anion accelerates towards the positive electrode.
As the ion moves through the solvent, it experiences a frictional
retarding force, Ffri, which is proportional to its speed, s.
Ffri = fs
Where,
f = 6a
a = radius of the solvated ion, = viscosity of the solvent (kgm-1s-1)
Drift Speed: The speed of an ion when the accelerating force is
balanced by the viscous drug.
F = Ffri ZeE = 6as
𝒔 =
𝒁𝒆𝑬
𝟔𝒂
16
17. Accordingly, the drift speed of an ion is proportional to the
strength of the applied field.
s E, hence
s = uE where u is ionic mobility.
Substitution yields:
Examples of ionic mobilities in water at 298 K
17
ion u (10-8 m2V-1s-1)
H+ 36.23
Na+ 5.19
K+ 7.62
OH- 20.64
Cl- 7.91
Br- 8.09
18. b) Mobility and Molar conductivity
The molar conductivity of an ion is proportional to the ion’s
mobility.
= 𝒖𝒁𝑭
Where F = Faraday’s constant = Nae
The equation applies to cations and anions.
+ = 𝒖+𝒁+𝑭 − = 𝒖−𝒁−𝑭
At infinite dilution the limiting molar conductivity is given by:
o
m = +𝒖+𝒁+ + −𝒖−𝒁− 𝑭
For a symmetrical z : z electrolyte (E.g. CuSO4, 2 : 2), the above
equation simplifies to:
o
m = 𝒁(𝒖+ + 𝒖−)F
Where Z = +Z+ = -Z-
18
,
19. c) Mobility and Diffusion Coefficient (D)
Example
If u+ = 5 10-8m2V-1s-1, at 25 oC,
d) Transport number
It is the fraction of total current carried by the ions of a specified
type.
Note: t+ + t- = 1 19
20. The limiting transport number, to, of an ion is related to the
mobility of the ion by:
+Z+ = -Z- - Electrical neutrality
Therefore,
Using the relationship between mobility and ionic conductivity,
Therefore,
20
21. Measuring Transport Number
It is measured using a moving boundary method.
Experiment
Apply a direct current to a solution.
The solution consists of;
- indicator solution E.g. a salt NX which is denser
- leading solution – E.g. a salt of interest – MX
21
K+ Cl-
Cd2+
Cl-
Initial Cd2+ boundary
Final Cd2+ boundary
Cathode
Anode
e-
e-
22. KCl – leading solution, CdCl2 – indicator solution
The mobility of K+ > Cd2+
The total charge passed across a cross – sectional area is:
Q = It
No. of K+ in the shaded region = NAcV = NAclA
Total charge of K+ in the shaded region in time t:
Q+ = Z+ eNAcV = Z+ FcV
Therefore, total charge transferred when a current I flows for time t
is:
By measuring the distance moved by the indicator solution, t,
and u of the ions can be determined.
22
23. Example:
In a moving boundary experiment a 0.1 M KCl solution was layered
above a CdCl2 solution in a tube of cross sectional area 0.276 cm2.
When 6.25 10-3 A was passed through for 4000 s the boundary
moved a distance of 4.6 cm.
Calculate the transport number of K+.
Solution
23
24. 1.3. Activity and Activity Coefficients
For an ideal solution, the chemical potential of a solute is given by:
Where, mB = molality of B
o
B = standard chemical potential – a chemical potential when
mB = 1molkg-1= mo
B
The equation holds for very dilute solutions (less than 10-3 molkg-1)
o
m = (+𝑢+𝑍+ + −𝑢−𝑍−)
For a real solution,
Where,
aB = activity of B, B = activity coefficient of B.
Note: B 1 asmB 0 24
25. 1.3.1. Activities of ions in solution:
The total molar Gibbs energy of the ions in ideal solution is the
sum of the chemical potential of the positive and the negative
ions.
Gm
ideal = +
ideal + -
ideal
For a real solution,
Gm = ++ - = +
ideal + -
ideal + RT ln + + RT ln- = Gm
ideal + RT ln+-
Gm becomes a function of the activities of the ions.
1.3.2. Mean activity coefficient (±)
It is the mean of the individual activity coefficients.
For a 1 : 1 electrolyte of univalent ions,
± = (+-)½
25
27. 1.3.3. Ionic strength
It is a measure of the non-ideality of an electrolyte solution which
is imposed by a solution containing ions.
Where Zi is charge of the ion, bi = molality, bo = 1molkg-1
Example
Calculate the ionic strength of a solution that contains 0.3 molal
NaOH and 0.1 molal Na3PO4.
Solution
bOH
- = 0.3 m, bPO4
3- = 0.1 m, bNa
+ = 0.3 + 3 0.1= 0.6 m
27
28. 1.3.4. The Debye – Hückel limiting law
The mean activity coefficient of an ionic solution depends on
a) ionic strength
b) Temperature
c) dielectric constant of the solvent
d) charge of the ions (Zi) given by the expression:
Where A = 0.509 for aqueous solution at 25 oC.
It is used to calculate the mean activity coefficient of an ionic
solution and holds for very low concentrations.
Note: The mean activity coefficient depends on the concentrations
of all ions in the solution.
28
29. Example: Calculate a) the ionic strength b) the mean activity
coefficient c) the activity of 1.00 mmolkg-1 CaCl2 (aq) at 25oC.
Solution
a)
ZCa
2+ = 2, ZCl
- = -1, bCa
2+ = 0.001molkg-1, bCl
- = 0.002 molkg-1
I = ½ (22 × 0.001 + -12 × 0.002) = 0.003
b) log = -0.509 Z+Z-I½ = -0.509 × 2 × (0.003)½ = -0.05599, = 0.879
c)
aA+B- = (m) =
m+
+-
- where, = + + -
aCaCl2 =
3m3 × 1 x 4 = (0.879)3 × (0.001)3 × 4 = 2.7166 × 10-6
29