This document discusses lattice energy and related concepts:
1) It defines lattice energy as the enthalpy change when one mole of an ionic solid forms from its gaseous ions, and explains how it depends on ion charge and radius.
2) Born-Haber cycles allow calculation of lattice energy by considering standard enthalpy changes in the step-wise formation of an ionic solid from its elements.
3) Ion polarization occurs when cation charge density and anion size lead to distortion of the anion electron cloud, influencing thermal stability.
This document discusses the properties and reactions of Group II elements and their compounds. It describes how atomic radius and ionization energy increase down the group, while electronegativity decreases. Group II elements react vigorously with oxygen and water to form oxides and hydroxides. Their oxides are basic and react with acids, while hydroxides are sparingly soluble bases. Thermal decomposition stability increases down the group for nitrates and carbonates. Important uses include magnesium oxide as a refractory and calcium compounds to make cement and treat acidic soil.
Chemistry zimsec chapter 8 chemical equilibriaalproelearning
(1) This document discusses chemical equilibria, including reversible reactions, factors that affect equilibrium, and acid-base theories.
(2) It describes how reversible reactions reach equilibrium when the rates of the forward and reverse reactions are equal. Le Chatelier's principle states that if a stress is applied to a system at equilibrium, it will shift in a way to counteract the stress.
(3) Equilibrium constants Kc and Kp are introduced, which do not depend on concentration or pressure changes. The Brønsted-Lowry acid-base theory defines acids as proton donors and bases as proton acceptors.
This document summarizes atomic structure and isotopes. It defines protons, neutrons, and electrons, and describes their relative masses and charges. It explains that the nucleus contains protons and neutrons, which make up most of an atom's mass. The document also discusses how subatomic particles behave in electric fields based on their charge. It defines nucleon number and proton number, and how they relate to the composition of atoms and ions. Finally, it defines isotopes as atoms of the same element with different numbers of neutrons, and notes they have similar chemical properties but different physical properties like mass.
Chemistry zimsec chapter 9 chemical periodicityalproelearning
This document summarizes key concepts about chemical periodicity, including the various blocks and periods in the periodic table. It describes trends in atomic properties like atomic radius, ionization energy, and electronegativity across periods and down groups. These trends are explained by factors like nuclear charge, atomic size, and shielding effects. Common reactions of representative elements like formation of oxides and chlorides from the third period are presented, along with equations. Structures and bonding of these compounds are discussed as well as their reactions with water.
Chemistry zimsec chapter 6 chemical energeticsalproelearning
1) The document discusses chemical energetics, specifically enthalpy changes, standard enthalpy changes, and Hess' law.
2) It defines exothermic and endothermic reactions, and explains how to calculate enthalpy changes from experimental temperature change data using standard formulas.
3) Standard enthalpy changes are discussed for various types of reactions including formation, combustion, neutralization, and others. Hess' law is introduced which states that the total enthalpy change is independent of reaction path as long as initial and final states are the same.
This document discusses lattice energy and related concepts:
1) It defines lattice energy as the enthalpy change when one mole of an ionic solid forms from its gaseous ions, and explains how it depends on ion charge and radius.
2) Born-Haber cycles allow calculation of lattice energy by considering standard enthalpy changes in the step-wise formation of an ionic solid from its elements.
3) Ion polarization occurs when cation charge density and anion size lead to distortion of the anion electron cloud, influencing thermal stability.
This document discusses the properties and reactions of Group II elements and their compounds. It describes how atomic radius and ionization energy increase down the group, while electronegativity decreases. Group II elements react vigorously with oxygen and water to form oxides and hydroxides. Their oxides are basic and react with acids, while hydroxides are sparingly soluble bases. Thermal decomposition stability increases down the group for nitrates and carbonates. Important uses include magnesium oxide as a refractory and calcium compounds to make cement and treat acidic soil.
Chemistry zimsec chapter 8 chemical equilibriaalproelearning
(1) This document discusses chemical equilibria, including reversible reactions, factors that affect equilibrium, and acid-base theories.
(2) It describes how reversible reactions reach equilibrium when the rates of the forward and reverse reactions are equal. Le Chatelier's principle states that if a stress is applied to a system at equilibrium, it will shift in a way to counteract the stress.
(3) Equilibrium constants Kc and Kp are introduced, which do not depend on concentration or pressure changes. The Brønsted-Lowry acid-base theory defines acids as proton donors and bases as proton acceptors.
This document summarizes atomic structure and isotopes. It defines protons, neutrons, and electrons, and describes their relative masses and charges. It explains that the nucleus contains protons and neutrons, which make up most of an atom's mass. The document also discusses how subatomic particles behave in electric fields based on their charge. It defines nucleon number and proton number, and how they relate to the composition of atoms and ions. Finally, it defines isotopes as atoms of the same element with different numbers of neutrons, and notes they have similar chemical properties but different physical properties like mass.
Chemistry zimsec chapter 9 chemical periodicityalproelearning
This document summarizes key concepts about chemical periodicity, including the various blocks and periods in the periodic table. It describes trends in atomic properties like atomic radius, ionization energy, and electronegativity across periods and down groups. These trends are explained by factors like nuclear charge, atomic size, and shielding effects. Common reactions of representative elements like formation of oxides and chlorides from the third period are presented, along with equations. Structures and bonding of these compounds are discussed as well as their reactions with water.
Chemistry zimsec chapter 6 chemical energeticsalproelearning
1) The document discusses chemical energetics, specifically enthalpy changes, standard enthalpy changes, and Hess' law.
2) It defines exothermic and endothermic reactions, and explains how to calculate enthalpy changes from experimental temperature change data using standard formulas.
3) Standard enthalpy changes are discussed for various types of reactions including formation, combustion, neutralization, and others. Hess' law is introduced which states that the total enthalpy change is independent of reaction path as long as initial and final states are the same.
1) Alcohols undergo several characteristic reactions including combustion producing carbon dioxide and water, dehydration producing alkenes, reaction with sodium producing alkoxides and hydrogen gas, and oxidation producing different products depending on whether the alcohol is primary, secondary, or tertiary.
2) Alcohols can be classified as primary, secondary, or tertiary depending on whether the carbon attached to the hydroxyl group has zero, one, or two alkyl groups respectively, and this classification determines how the alcohol will react during oxidation.
3) Esterification involves heating an alcohol and a carboxylic acid together with a catalyst such as sulfuric acid to produce an ester, with the general form of R
1. Electrochemistry involves redox reactions where one element is oxidized and another is reduced. Oxidation is the loss of electrons and an increase in oxidation number, while reduction is the gain of electrons and a decrease in oxidation number.
2. Electrolysis is the passage of an electric current through an ionic substance to cause a non-spontaneous redox reaction. Oxidation occurs at the anode and reduction at the cathode.
3. Aluminum is extracted from bauxite via electrolysis. Bauxite is dissolved in molten cryolite to lower its melting point, then electrolysis separates aluminum ions at the cathode.
The document discusses the physical and chemical properties of Group IV elements and their compounds. It covers:
1) The variation in properties like melting point, electrical conductivity down the group due to changes in bonding and structure.
2) The tetrachlorides of Group IV elements which are volatile liquids that hydrolyze in water, with reactivity increasing down the group.
3) The two types of oxides formed - monoxides and dioxides. Their structures, acid-base properties and thermal stability are explained.
4) The relative stability of the +2 and +4 oxidation states decreases and increases down the group respectively. This affects the redox behavior of the elements.
Zimsec chemistry chapter 9 rate of reactionalproelearning
This document discusses factors that affect the rate of chemical reactions, including concentration, temperature, surface area, pressure, and catalysis. It defines rate of reaction, activation energy, and catalysts. It explains qualitatively how increasing concentration, temperature, and surface area increases the rate of reaction by increasing collision frequency and effective collisions. It describes how catalysts lower the activation energy of reactions, and enzymes act as biological catalysts with high specificity.
Chemistry zimsec chapter 2 atoms, molecules and stoichiometryalproelearning
This document provides an overview of Chapter 2 in a chemistry textbook, which covers topics including:
- The mass of atoms and molecules, including relative atomic mass and molecular mass
- Using a mass spectrometer to determine relative isotopic masses and abundances
- The mole concept and amount of substance in relation to mass, volume of gases, and concentration of solutions
- Calculating empirical formulas from combustion data or elemental composition by mass and deducing molecular formulas
- Stoichiometry, including writing balanced chemical equations and ionic equations
This document summarizes key information about halogenoalkanes:
- Halogenoalkanes undergo nucleophilic substitution reactions like hydrolysis and reactions with cyanide ions or ammonia via SN1 or SN2 mechanisms. Tertiary halogenoalkanes favor SN1 while primary favor SN2.
- Chlorofluorocarbons (CFCs) were widely used but deplete the ozone layer. Their alternatives like HCFCs are less damaging but still pose issues.
- Other uses of halogenoalkanes include their inertness making fluoroalkanes useful as refrigerants and propellants, though concerns about ozone depletion drove a search for replacements like propane
This document provides an overview of transition elements and their properties including:
1) Transition elements have variable oxidation states due to their similar energy 4s and 3d electron levels. They can gain or lose electrons to form stable ions.
2) Transition elements form colored complexes when surrounded by ligands via coordinate bonding. Ligand exchange reactions can replace one ligand for another.
3) The shapes and colors of transition metal complexes are determined by the ligands present and the splitting of d orbitals. Different ligands cause different color changes through electron movement between d orbitals.
This document discusses reaction kinetics including:
1) Rate equations relate the rate of reaction to reactant concentrations and can be determined experimentally. The orders of reaction indicate how changing concentrations affect rate.
2) Reaction mechanisms involve multiple steps, with the rate determined by the slowest step. Molecularity refers to the number of species involved in a step.
3) Catalysts increase reaction rates by providing alternative reaction pathways. Heterogeneous catalysts involve different phases while homogeneous catalysts are the same phase as reactants. Common examples are discussed.
This document provides an overview of Chapter 22 from a chemistry textbook, which covers topics related to ionic equilibria including:
- pH, Ka, pKa and Kw values and their use in calculations involving strong and weak acids and bases.
- Acid-base titration curves and how they differ for strong-strong, strong-weak, weak-strong, and weak-weak acid-base titrations.
- How acid-base indicators work and their use in determining the endpoint of a titration.
It also lists learning outcomes for understanding these concepts and performing related calculations.
Chemistry zimsec chapter 3 electrons in atomsalproelearning
This document discusses electron configurations and ionization energies. It begins by describing electron arrangements in atoms based on principal and sub-shell quantum numbers. Rules for filling orbitals like the Aufbau principle and Hund's rule are explained. Electronic configurations are given for elements up to zinc. Factors that influence ionization energies like nuclear charge and shielding are outlined. Trends in ionization energy across periods and down groups are described. Successive ionization data can reveal an element's electron configuration and position in the periodic table.
1) Hydrocarbons are compounds made of only carbon and hydrogen. This chapter discusses the properties, reactions and uses of two main types of hydrocarbons - alkanes and alkenes.
2) Alkanes are saturated and generally unreactive. They undergo combustion and halogenation reactions. Alkenes contain a carbon-carbon double bond and mainly undergo electrophilic addition reactions.
3) Crude oil is a major source of hydrocarbons and fractional distillation is used to separate the different hydrocarbons based on their boiling points. Hydrocarbons are used as fuels and in the production of numerous materials like plastics.
Chemistry zimsec chapter 4 chemical bondingalproelearning
The document summarizes key concepts about chemical bonding. It discusses ionic bonding through the transfer of electrons to form cations and anions, and covalent bonding through the sharing of electron pairs. It describes different types of covalent bonds like single, double, and triple bonds. The shapes of molecules are explained using valence shell electron pair repulsion theory. Hybridization of atomic orbitals is introduced to describe molecular geometry and bonding in methane, ethene, and ethyne. Other topics covered include intermolecular forces, metallic bonding, and how bonding affects physical properties.
Accounting 970643 paper 4 problem solving (supplementary topics) october nove...alproelearning
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1) Alcohols undergo several characteristic reactions including combustion producing carbon dioxide and water, dehydration producing alkenes, reaction with sodium producing alkoxides and hydrogen gas, and oxidation producing different products depending on whether the alcohol is primary, secondary, or tertiary.
2) Alcohols can be classified as primary, secondary, or tertiary depending on whether the carbon attached to the hydroxyl group has zero, one, or two alkyl groups respectively, and this classification determines how the alcohol will react during oxidation.
3) Esterification involves heating an alcohol and a carboxylic acid together with a catalyst such as sulfuric acid to produce an ester, with the general form of R
1. Electrochemistry involves redox reactions where one element is oxidized and another is reduced. Oxidation is the loss of electrons and an increase in oxidation number, while reduction is the gain of electrons and a decrease in oxidation number.
2. Electrolysis is the passage of an electric current through an ionic substance to cause a non-spontaneous redox reaction. Oxidation occurs at the anode and reduction at the cathode.
3. Aluminum is extracted from bauxite via electrolysis. Bauxite is dissolved in molten cryolite to lower its melting point, then electrolysis separates aluminum ions at the cathode.
The document discusses the physical and chemical properties of Group IV elements and their compounds. It covers:
1) The variation in properties like melting point, electrical conductivity down the group due to changes in bonding and structure.
2) The tetrachlorides of Group IV elements which are volatile liquids that hydrolyze in water, with reactivity increasing down the group.
3) The two types of oxides formed - monoxides and dioxides. Their structures, acid-base properties and thermal stability are explained.
4) The relative stability of the +2 and +4 oxidation states decreases and increases down the group respectively. This affects the redox behavior of the elements.
Zimsec chemistry chapter 9 rate of reactionalproelearning
This document discusses factors that affect the rate of chemical reactions, including concentration, temperature, surface area, pressure, and catalysis. It defines rate of reaction, activation energy, and catalysts. It explains qualitatively how increasing concentration, temperature, and surface area increases the rate of reaction by increasing collision frequency and effective collisions. It describes how catalysts lower the activation energy of reactions, and enzymes act as biological catalysts with high specificity.
Chemistry zimsec chapter 2 atoms, molecules and stoichiometryalproelearning
This document provides an overview of Chapter 2 in a chemistry textbook, which covers topics including:
- The mass of atoms and molecules, including relative atomic mass and molecular mass
- Using a mass spectrometer to determine relative isotopic masses and abundances
- The mole concept and amount of substance in relation to mass, volume of gases, and concentration of solutions
- Calculating empirical formulas from combustion data or elemental composition by mass and deducing molecular formulas
- Stoichiometry, including writing balanced chemical equations and ionic equations
This document summarizes key information about halogenoalkanes:
- Halogenoalkanes undergo nucleophilic substitution reactions like hydrolysis and reactions with cyanide ions or ammonia via SN1 or SN2 mechanisms. Tertiary halogenoalkanes favor SN1 while primary favor SN2.
- Chlorofluorocarbons (CFCs) were widely used but deplete the ozone layer. Their alternatives like HCFCs are less damaging but still pose issues.
- Other uses of halogenoalkanes include their inertness making fluoroalkanes useful as refrigerants and propellants, though concerns about ozone depletion drove a search for replacements like propane
This document provides an overview of transition elements and their properties including:
1) Transition elements have variable oxidation states due to their similar energy 4s and 3d electron levels. They can gain or lose electrons to form stable ions.
2) Transition elements form colored complexes when surrounded by ligands via coordinate bonding. Ligand exchange reactions can replace one ligand for another.
3) The shapes and colors of transition metal complexes are determined by the ligands present and the splitting of d orbitals. Different ligands cause different color changes through electron movement between d orbitals.
This document discusses reaction kinetics including:
1) Rate equations relate the rate of reaction to reactant concentrations and can be determined experimentally. The orders of reaction indicate how changing concentrations affect rate.
2) Reaction mechanisms involve multiple steps, with the rate determined by the slowest step. Molecularity refers to the number of species involved in a step.
3) Catalysts increase reaction rates by providing alternative reaction pathways. Heterogeneous catalysts involve different phases while homogeneous catalysts are the same phase as reactants. Common examples are discussed.
This document provides an overview of Chapter 22 from a chemistry textbook, which covers topics related to ionic equilibria including:
- pH, Ka, pKa and Kw values and their use in calculations involving strong and weak acids and bases.
- Acid-base titration curves and how they differ for strong-strong, strong-weak, weak-strong, and weak-weak acid-base titrations.
- How acid-base indicators work and their use in determining the endpoint of a titration.
It also lists learning outcomes for understanding these concepts and performing related calculations.
Chemistry zimsec chapter 3 electrons in atomsalproelearning
This document discusses electron configurations and ionization energies. It begins by describing electron arrangements in atoms based on principal and sub-shell quantum numbers. Rules for filling orbitals like the Aufbau principle and Hund's rule are explained. Electronic configurations are given for elements up to zinc. Factors that influence ionization energies like nuclear charge and shielding are outlined. Trends in ionization energy across periods and down groups are described. Successive ionization data can reveal an element's electron configuration and position in the periodic table.
1) Hydrocarbons are compounds made of only carbon and hydrogen. This chapter discusses the properties, reactions and uses of two main types of hydrocarbons - alkanes and alkenes.
2) Alkanes are saturated and generally unreactive. They undergo combustion and halogenation reactions. Alkenes contain a carbon-carbon double bond and mainly undergo electrophilic addition reactions.
3) Crude oil is a major source of hydrocarbons and fractional distillation is used to separate the different hydrocarbons based on their boiling points. Hydrocarbons are used as fuels and in the production of numerous materials like plastics.
Chemistry zimsec chapter 4 chemical bondingalproelearning
The document summarizes key concepts about chemical bonding. It discusses ionic bonding through the transfer of electrons to form cations and anions, and covalent bonding through the sharing of electron pairs. It describes different types of covalent bonds like single, double, and triple bonds. The shapes of molecules are explained using valence shell electron pair repulsion theory. Hybridization of atomic orbitals is introduced to describe molecular geometry and bonding in methane, ethene, and ethyne. Other topics covered include intermolecular forces, metallic bonding, and how bonding affects physical properties.
Accounting 970643 paper 4 problem solving (supplementary topics) october nove...alproelearning
Accounting 970643 paper 4 problem solving (supplementary topics) october november 2014
Advanced Level
A Level
Zimsec
Cambridge
Alpro Learning Portal
Accounting
Accounts
Zimbabwe
Principle of accounts
Accounting 970642 paper 4 problem solving (supplementary topics) october nove...alproelearning
Accounting 970642 paper 4 problem solving (supplementary topics) october november 2013
Advanced Level
A Level
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Accounting
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Principle of accounts
Accounting 970643 paper 4 problem solving (supplementary topics) october nove...alproelearning
Accounting 970643 paper 4 problem solving (supplementary topics) october november 2012
Advanced Level
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Accounting
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Principle of accounts
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This document provides an overview of wound healing, its functions, stages, mechanisms, factors affecting it, and complications.
A wound is a break in the integrity of the skin or tissues, which may be associated with disruption of the structure and function.
Healing is the body’s response to injury in an attempt to restore normal structure and functions.
Healing can occur in two ways: Regeneration and Repair
There are 4 phases of wound healing: hemostasis, inflammation, proliferation, and remodeling. This document also describes the mechanism of wound healing. Factors that affect healing include infection, uncontrolled diabetes, poor nutrition, age, anemia, the presence of foreign bodies, etc.
Complications of wound healing like infection, hyperpigmentation of scar, contractures, and keloid formation.
Temple of Asclepius in Thrace. Excavation resultsKrassimira Luka
The temple and the sanctuary around were dedicated to Asklepios Zmidrenus. This name has been known since 1875 when an inscription dedicated to him was discovered in Rome. The inscription is dated in 227 AD and was left by soldiers originating from the city of Philippopolis (modern Plovdiv).
Elevate Your Nonprofit's Online Presence_ A Guide to Effective SEO Strategies...TechSoup
Whether you're new to SEO or looking to refine your existing strategies, this webinar will provide you with actionable insights and practical tips to elevate your nonprofit's online presence.
How to Manage Reception Report in Odoo 17Celine George
A business may deal with both sales and purchases occasionally. They buy things from vendors and then sell them to their customers. Such dealings can be confusing at times. Because multiple clients may inquire about the same product at the same time, after purchasing those products, customers must be assigned to them. Odoo has a tool called Reception Report that can be used to complete this assignment. By enabling this, a reception report comes automatically after confirming a receipt, from which we can assign products to orders.
Gender and Mental Health - Counselling and Family Therapy Applications and In...PsychoTech Services
A proprietary approach developed by bringing together the best of learning theories from Psychology, design principles from the world of visualization, and pedagogical methods from over a decade of training experience, that enables you to: Learn better, faster!
Andreas Schleicher presents PISA 2022 Volume III - Creative Thinking - 18 Jun...EduSkills OECD
Andreas Schleicher, Director of Education and Skills at the OECD presents at the launch of PISA 2022 Volume III - Creative Minds, Creative Schools on 18 June 2024.