The document discusses the rate of reaction and factors that affect it. It defines rate of reaction as the change in amount of reactant or product per unit time. The rate depends on concentration, temperature, surface area, and other factors. Higher concentrations and temperatures increase the rate by increasing collisions between reactant particles. Smaller particle sizes also increase the rate by providing more surface area for reactions. Graphs and experiments are described to illustrate these relationships.
1) Several factors that affect the rate of chemical reactions are discussed, including the size of reactants, concentration of solutions, temperature, and presence of catalysts.
2) When the size of reactants is smaller, the total surface area exposed to collisions increases, leading to a higher rate of reaction.
3) A higher concentration of reactants means more particles per unit volume, resulting in more frequent collisions and a faster rate.
4) At higher temperatures, reactant particles have greater kinetic energy to overcome the activation energy barrier, increasing the frequency of effective collisions and accelerating the rate.
5) Catalysts provide an alternative reaction pathway requiring lower activation energy, allowing more particles to react effectively and speed
Here are the effects on the rate of reaction of changing each condition:
- If the concentration of acid is increased, the rate of reaction will increase. This is because there will be more reactant particles per unit volume, resulting in more frequent collisions between reactants.
- If calcium carbonate powder is used instead of small pieces, the rate of reaction will increase. This is because powder has a larger surface area, allowing for more reactant particles at the interface where the reaction occurs.
- If the volume of acid is increased, the rate of reaction will initially increase but then level off. This is because there will be more reactant particles initially, but the reaction will use them up over time.
- If the
The document discusses the rate of chemical reactions and factors that affect it. It provides examples of reactions that occur at different rates and how rate is calculated. The average rate and instantaneous rate are defined. Experiments are described to determine the effect of surface area, concentration, temperature, catalyst, and pressure on the reaction rate. The concept of effective collision is introduced, where particles must collide with sufficient energy and correct orientation for a reaction to occur. Factors that increase collision frequency or lower activation energy can increase the reaction rate.
The document discusses kinetics and the rate law for the decolorization of crystal violet. It describes using a spectroscopic colorimeter to monitor the concentration of crystal violet over time as it reacts with sodium hydroxide. The goals are to determine the overall rate law and rate constant k for the decolorization reaction. Experiments are conducted at different concentrations and the orders are determined by analyzing linear regression graphs of integrated rate laws versus time and concentration. The 1st order graph provided the best correlation, indicating the reaction is first order with respect to crystal violet concentration.
This document discusses reaction rates and kinetics. It defines reaction rate as the change in concentration of a reactant or product over time. The four main factors that influence reaction rate are: the state of reactants, temperature, concentration of reactants, and presence of a catalyst. An example reaction is provided and reaction rates are calculated at different time intervals from concentration data. Instantaneous and average reaction rates are compared. Reaction order and rate laws are introduced, and examples are shown of determining the rate law from experimental data by analyzing how the rate changes with varying concentrations.
CHE116 - Week 2: reaction rates and reaction orderSadie Novak
This document discusses reaction rates and kinetics. It defines reaction rate and explains that the rate depends on concentration, temperature, surface area, and presence of a catalyst. Four factors that influence reaction rate are identified: state of reactants, temperature, concentration, and presence of a catalyst. An example reaction is provided and rate is calculated using concentration data. Reaction order and rate laws are introduced. Determining reaction order experimentally and writing rate laws based on reaction data are explained. Forming study groups is offered.
1. The document discusses factors that affect the rate of chemical reactions, including temperature, concentration, pressure, surface area, and catalysts.
2. It explains that the rate of a reaction is measured by how concentration changes over time, and that rate laws use rate constants and reaction orders.
3. Different factors like increased temperature, concentration, or pressure speed up reactions by increasing the frequency of successful collisions between reactant particles.
A reaction can be either fast or slow depending on the time taken. A fast reaction has a short time and high rate, while a slow reaction has a long time and low rate. The rate of reaction depends on factors like concentration, temperature, surface area, and catalysts. Collisions between reactant particles must be effective, with sufficient energy to overcome the activation energy barrier, in order for reactions to occur.
1) Several factors that affect the rate of chemical reactions are discussed, including the size of reactants, concentration of solutions, temperature, and presence of catalysts.
2) When the size of reactants is smaller, the total surface area exposed to collisions increases, leading to a higher rate of reaction.
3) A higher concentration of reactants means more particles per unit volume, resulting in more frequent collisions and a faster rate.
4) At higher temperatures, reactant particles have greater kinetic energy to overcome the activation energy barrier, increasing the frequency of effective collisions and accelerating the rate.
5) Catalysts provide an alternative reaction pathway requiring lower activation energy, allowing more particles to react effectively and speed
Here are the effects on the rate of reaction of changing each condition:
- If the concentration of acid is increased, the rate of reaction will increase. This is because there will be more reactant particles per unit volume, resulting in more frequent collisions between reactants.
- If calcium carbonate powder is used instead of small pieces, the rate of reaction will increase. This is because powder has a larger surface area, allowing for more reactant particles at the interface where the reaction occurs.
- If the volume of acid is increased, the rate of reaction will initially increase but then level off. This is because there will be more reactant particles initially, but the reaction will use them up over time.
- If the
The document discusses the rate of chemical reactions and factors that affect it. It provides examples of reactions that occur at different rates and how rate is calculated. The average rate and instantaneous rate are defined. Experiments are described to determine the effect of surface area, concentration, temperature, catalyst, and pressure on the reaction rate. The concept of effective collision is introduced, where particles must collide with sufficient energy and correct orientation for a reaction to occur. Factors that increase collision frequency or lower activation energy can increase the reaction rate.
The document discusses kinetics and the rate law for the decolorization of crystal violet. It describes using a spectroscopic colorimeter to monitor the concentration of crystal violet over time as it reacts with sodium hydroxide. The goals are to determine the overall rate law and rate constant k for the decolorization reaction. Experiments are conducted at different concentrations and the orders are determined by analyzing linear regression graphs of integrated rate laws versus time and concentration. The 1st order graph provided the best correlation, indicating the reaction is first order with respect to crystal violet concentration.
This document discusses reaction rates and kinetics. It defines reaction rate as the change in concentration of a reactant or product over time. The four main factors that influence reaction rate are: the state of reactants, temperature, concentration of reactants, and presence of a catalyst. An example reaction is provided and reaction rates are calculated at different time intervals from concentration data. Instantaneous and average reaction rates are compared. Reaction order and rate laws are introduced, and examples are shown of determining the rate law from experimental data by analyzing how the rate changes with varying concentrations.
CHE116 - Week 2: reaction rates and reaction orderSadie Novak
This document discusses reaction rates and kinetics. It defines reaction rate and explains that the rate depends on concentration, temperature, surface area, and presence of a catalyst. Four factors that influence reaction rate are identified: state of reactants, temperature, concentration, and presence of a catalyst. An example reaction is provided and rate is calculated using concentration data. Reaction order and rate laws are introduced. Determining reaction order experimentally and writing rate laws based on reaction data are explained. Forming study groups is offered.
1. The document discusses factors that affect the rate of chemical reactions, including temperature, concentration, pressure, surface area, and catalysts.
2. It explains that the rate of a reaction is measured by how concentration changes over time, and that rate laws use rate constants and reaction orders.
3. Different factors like increased temperature, concentration, or pressure speed up reactions by increasing the frequency of successful collisions between reactant particles.
A reaction can be either fast or slow depending on the time taken. A fast reaction has a short time and high rate, while a slow reaction has a long time and low rate. The rate of reaction depends on factors like concentration, temperature, surface area, and catalysts. Collisions between reactant particles must be effective, with sufficient energy to overcome the activation energy barrier, in order for reactions to occur.
This document discusses chemical kinetics and rate of reactions. It defines chemical kinetics as the study of reaction rates and their mechanisms. It then discusses factors that influence reaction rates such as concentration, temperature, pressure, catalysts and more. It defines rate of reaction and discusses how to determine rates. It introduces reaction orders such as zero order, first order and second order reactions. Examples of each type of reaction order are provided along with the appropriate rate equations. Pseudo-first order reactions are also discussed.
The document provides information about measuring gas volumes produced in chemical reactions, including:
1. Methods to measure gas volumes using apparatus like gas syringes and measuring cylinders.
2. Examples of reactions that produce gas volumes like Mg + 2HCl and CaCO3 + 2HCl.
3. Factors that determine gas volumes like the amount of limiting reactant and excess reactant.
Reaction Kinetics.really detailed and educationalHayaaKhan8
The document discusses reaction kinetics and factors that affect the rate of chemical reactions. It defines the rate of reaction as the change in concentration of reactants or products over time. The rate can be determined from concentration-time graphs by calculating the slope of the tangent line. The rate is directly proportional to the concentration of reactants for most reactions. Temperature also affects the rate, as increasing temperature results in more particles with energy greater than the activation energy according to Maxwell-Boltzmann distribution. Catalysts increase the rate of reaction by providing an alternative reaction pathway with lower activation energy.
The document discusses fire extinguishers that use a chemical reaction to extinguish fires. Specifically, it describes soda-acid fire extinguishers, which contain a bottle of sulfuric acid and a container of sodium bicarbonate solution. When the extinguisher is activated, the acid and solution mix and react, producing carbon dioxide gas. This pressurizes the water inside and forces it out to extinguish the fire. The reaction between the sodium bicarbonate solution and sulfuric acid produces carbon dioxide and water, pressurizing the extinguisher.
The document discusses rate of reaction and factors that affect it. It defines rate of reaction as the change in amount of reactants or products per unit time. It describes several factors that affect rate based on collision theory, including surface area, concentration, temperature, catalysts, and pressure. It gives examples of how scientific understanding of rate of reaction enhances quality of life, such as refrigeration, pressure cooking, cutting food into smaller pieces, making margarine, and burning coal.
The document provides an outline and notes on the topics of rate of reaction, collision theory, factors affecting reaction rates, activation energy, endothermic and exothermic reactions, equilibrium, and Le Chatelier's principle. Key points include:
- Reaction rates can be determined by measuring how quickly reactants are used up or products are formed. Temperature, catalysts, surface area, and concentration can impact reaction rates.
- Collision theory states that reactants must collide with sufficient energy and correct orientation for a reaction to occur, forming an intermediate activated complex.
- Equilibrium is reached when the rates of the forward and reverse reactions are equal, though concentrations of reactants and products may not be equal.
-
a detailed description of the chapter chemical kinetics (physical chemistry) including different problems by Dr. Satyabrata Si from KIIT school of biotechnology
The document discusses chemical equilibrium. It begins by defining chemical equilibrium as a state where the forward and reverse reaction rates are equal, but the reactions are still occurring dynamically. It also notes that at equilibrium, the concentrations or pressures of all species remain constant over time. The document then provides the definitions and expressions for equilibrium constants Kc and Kp, which relate the concentrations or pressures of reactants and products at equilibrium. It also discusses how equilibrium positions can be manipulated by changing conditions based on Le Chatelier's principle.
This document discusses chemical kinetics, which is the study of reaction rates and how reaction rates change under varying conditions. Chemical kinetics is an empirical and experimental area of study that allows investigation of reaction mechanisms. Kinetic studies involve measuring reaction rates at different reactant concentrations and time intervals to determine the rate law equation and rate constant for a reaction. The rate law relates the reaction rate to the concentrations of reactants in the reaction and can provide information about the reaction mechanism and steps.
This document discusses chemical kinetics and reaction rates. It defines different types of reaction rates, including average reaction velocity, instantaneous rate of reaction, and specific reaction rate. Factors that affect the rate of reaction are also examined, such as concentration, temperature, surface area, and catalysts. Examples are provided to illustrate concepts like determining rates of appearance and disappearance based on chemical equations. The key aspects covered in 3 sentences or less are: Chemical kinetics deals with reaction rates and their relationship to experimental factors. Different methods for calculating rates are outlined, including instantaneous rate determined from the slope of concentration-time graphs. Specific reaction rates are proportional to reactant concentrations raised to their stoichiometric coefficients as defined by rate laws.
The document discusses rates of reaction and reaction order. It provides examples of how to calculate average rates of reaction using concentration data over time. It also explains how to determine the rate law and reaction order of a reaction by analyzing rate data at different concentrations of reactants. The overall reaction order is found by adding the orders of each reactant. Higher concentrations of reactants increase the rate according to the rate law.
The document defines rate of reaction as the change in amount of reactants or products over time. It provides examples of fast and slow reactions. Rate can be determined by measuring decreases in reactants or increases in products over time. For reactions where quantities are immeasurable, rate is determined by time for a measurable change like color change. Graphs of quantity over time can be used to determine average rate from the slope or instantaneous rate from the tangent slope at a point. Examples show calculating rates from graphs, tables, and chemical equations.
This experiment involves conducting a saponification reaction between sodium hydroxide (NaOH) and ethyl acetate (Et(Ac)) in a continuous stirred tank reactor (CSTR) to determine the effect of residence time on conversion. A calibration curve will be prepared to relate conductivity measurements to conversion values for the 0.1M NaOH and 0.1M Et(Ac) reaction. The objectives are to determine conversion, the reaction rate constant, and the effect of residence time on conversion.
Chemical kinetics, equilibrium and energeticsMussaOmary3
This document discusses chemical kinetics, equilibrium, and energetics. It covers the rate of chemical reactions, factors that affect rate such as temperature, concentration, catalysts, and surface area. It also discusses reversible and irreversible reactions, chemical equilibrium, and factors that affect equilibrium like temperature, pressure, and concentration. Finally, it defines exothermic and endothermic reactions, and uses energy level diagrams to illustrate the differences.
1. The document outlines a secondary school chemistry programme covering rates of reaction.
2. It discusses how factors like concentration, temperature, and surface area affect the rate of reactions. Experiments are described to investigate these effects.
3. The programme covers topics over 5 weeks, including graphical interpretation of rate data, exothermic and endothermic reactions, heat of reactions, and an energetics review. Lessons provide definitions, explanations, worksheets, and balanced equations.
The document discusses various topics related to chemical kinetics including:
- Definitions of rate of reaction, instantaneous rate, and average rate.
- Integrated rate equations for zero-order and first-order reactions and how to determine the half-life of a first-order reaction from its rate constant.
- The Arrhenius equation and how it relates the temperature dependence of reaction rates to activation energy. Increasing temperature increases the fraction of molecules with energy exceeding the activation energy.
- How catalysts increase reaction rates by providing an alternative reaction pathway requiring lower activation energy.
Rate of reaction for limestone and citric acid.dhmcmillan
The document describes an experiment to measure the rate of reaction between calcium carbonate and citric acid. Calcium carbonate and citric acid react to produce calcium citrate, carbon dioxide gas, and water. The rate of reaction is measured by determining the volume of carbon dioxide gas produced over time as it is a product of the reaction. The results are recorded in a table showing the volume of carbon dioxide detected after various time intervals. These results can then be used to calculate values like the rate of reaction and number of moles of carbon dioxide produced.
The document discusses kinetics and reaction rates. It defines kinetics as the study of reaction rates, and explains that thermodynamics determines if a reaction will occur but not how fast. It then covers factors that affect reaction rates like temperature, concentration, and catalysts. The document provides examples of calculating rates from concentration data and determining rate laws from experimental results. It also introduces integrated rate laws and how to determine reaction order from different rate law equations.
The document summarizes an experiment investigating the effect of concentration and temperature on the rate of a Harcourt-Essen reaction. By varying the concentration of iodide ions between runs, the reaction was found to be second order overall and first order with respect to both peroxide ions and iodide ions. Increasing the temperature between runs caused the rate coefficient to increase, demonstrating that the reaction rate increases with temperature in accordance with the Arrhenius equation.
This document discusses chemical kinetics and reaction rates. It begins with an introduction to chemical kinetics and defines reaction rate. It then discusses factors that affect reaction rates such as nature of reactants, concentration, temperature, and catalysts. It describes different types of reaction rates and how they are measured. The document also covers rate laws, determining rate orders experimentally, and integrated and differential rate equations for zero, first, and second order reactions. It concludes with an overview of rate theories including the Arrhenius equation.
1. Photosynthesis converts sunlight into chemical energy through two stages - the light-dependent reactions which produce ATP and NADPH using chlorophyll, and the light-independent Calvin cycle which uses these products to fix carbon and produce glucose.
2. The light-dependent reactions take place in the thylakoid membranes of the chloroplast and involve the absorption of light by photosystems and electron transport chains to generate a proton gradient for ATP synthesis via chemiosmosis.
3. The light-independent Calvin cycle occurs in the chloroplast stroma and uses the ATP and NADPH from the light reactions to reduce carbon dioxide and produce glucose through a series of reduction
This document discusses chemical kinetics and rate of reactions. It defines chemical kinetics as the study of reaction rates and their mechanisms. It then discusses factors that influence reaction rates such as concentration, temperature, pressure, catalysts and more. It defines rate of reaction and discusses how to determine rates. It introduces reaction orders such as zero order, first order and second order reactions. Examples of each type of reaction order are provided along with the appropriate rate equations. Pseudo-first order reactions are also discussed.
The document provides information about measuring gas volumes produced in chemical reactions, including:
1. Methods to measure gas volumes using apparatus like gas syringes and measuring cylinders.
2. Examples of reactions that produce gas volumes like Mg + 2HCl and CaCO3 + 2HCl.
3. Factors that determine gas volumes like the amount of limiting reactant and excess reactant.
Reaction Kinetics.really detailed and educationalHayaaKhan8
The document discusses reaction kinetics and factors that affect the rate of chemical reactions. It defines the rate of reaction as the change in concentration of reactants or products over time. The rate can be determined from concentration-time graphs by calculating the slope of the tangent line. The rate is directly proportional to the concentration of reactants for most reactions. Temperature also affects the rate, as increasing temperature results in more particles with energy greater than the activation energy according to Maxwell-Boltzmann distribution. Catalysts increase the rate of reaction by providing an alternative reaction pathway with lower activation energy.
The document discusses fire extinguishers that use a chemical reaction to extinguish fires. Specifically, it describes soda-acid fire extinguishers, which contain a bottle of sulfuric acid and a container of sodium bicarbonate solution. When the extinguisher is activated, the acid and solution mix and react, producing carbon dioxide gas. This pressurizes the water inside and forces it out to extinguish the fire. The reaction between the sodium bicarbonate solution and sulfuric acid produces carbon dioxide and water, pressurizing the extinguisher.
The document discusses rate of reaction and factors that affect it. It defines rate of reaction as the change in amount of reactants or products per unit time. It describes several factors that affect rate based on collision theory, including surface area, concentration, temperature, catalysts, and pressure. It gives examples of how scientific understanding of rate of reaction enhances quality of life, such as refrigeration, pressure cooking, cutting food into smaller pieces, making margarine, and burning coal.
The document provides an outline and notes on the topics of rate of reaction, collision theory, factors affecting reaction rates, activation energy, endothermic and exothermic reactions, equilibrium, and Le Chatelier's principle. Key points include:
- Reaction rates can be determined by measuring how quickly reactants are used up or products are formed. Temperature, catalysts, surface area, and concentration can impact reaction rates.
- Collision theory states that reactants must collide with sufficient energy and correct orientation for a reaction to occur, forming an intermediate activated complex.
- Equilibrium is reached when the rates of the forward and reverse reactions are equal, though concentrations of reactants and products may not be equal.
-
a detailed description of the chapter chemical kinetics (physical chemistry) including different problems by Dr. Satyabrata Si from KIIT school of biotechnology
The document discusses chemical equilibrium. It begins by defining chemical equilibrium as a state where the forward and reverse reaction rates are equal, but the reactions are still occurring dynamically. It also notes that at equilibrium, the concentrations or pressures of all species remain constant over time. The document then provides the definitions and expressions for equilibrium constants Kc and Kp, which relate the concentrations or pressures of reactants and products at equilibrium. It also discusses how equilibrium positions can be manipulated by changing conditions based on Le Chatelier's principle.
This document discusses chemical kinetics, which is the study of reaction rates and how reaction rates change under varying conditions. Chemical kinetics is an empirical and experimental area of study that allows investigation of reaction mechanisms. Kinetic studies involve measuring reaction rates at different reactant concentrations and time intervals to determine the rate law equation and rate constant for a reaction. The rate law relates the reaction rate to the concentrations of reactants in the reaction and can provide information about the reaction mechanism and steps.
This document discusses chemical kinetics and reaction rates. It defines different types of reaction rates, including average reaction velocity, instantaneous rate of reaction, and specific reaction rate. Factors that affect the rate of reaction are also examined, such as concentration, temperature, surface area, and catalysts. Examples are provided to illustrate concepts like determining rates of appearance and disappearance based on chemical equations. The key aspects covered in 3 sentences or less are: Chemical kinetics deals with reaction rates and their relationship to experimental factors. Different methods for calculating rates are outlined, including instantaneous rate determined from the slope of concentration-time graphs. Specific reaction rates are proportional to reactant concentrations raised to their stoichiometric coefficients as defined by rate laws.
The document discusses rates of reaction and reaction order. It provides examples of how to calculate average rates of reaction using concentration data over time. It also explains how to determine the rate law and reaction order of a reaction by analyzing rate data at different concentrations of reactants. The overall reaction order is found by adding the orders of each reactant. Higher concentrations of reactants increase the rate according to the rate law.
The document defines rate of reaction as the change in amount of reactants or products over time. It provides examples of fast and slow reactions. Rate can be determined by measuring decreases in reactants or increases in products over time. For reactions where quantities are immeasurable, rate is determined by time for a measurable change like color change. Graphs of quantity over time can be used to determine average rate from the slope or instantaneous rate from the tangent slope at a point. Examples show calculating rates from graphs, tables, and chemical equations.
This experiment involves conducting a saponification reaction between sodium hydroxide (NaOH) and ethyl acetate (Et(Ac)) in a continuous stirred tank reactor (CSTR) to determine the effect of residence time on conversion. A calibration curve will be prepared to relate conductivity measurements to conversion values for the 0.1M NaOH and 0.1M Et(Ac) reaction. The objectives are to determine conversion, the reaction rate constant, and the effect of residence time on conversion.
Chemical kinetics, equilibrium and energeticsMussaOmary3
This document discusses chemical kinetics, equilibrium, and energetics. It covers the rate of chemical reactions, factors that affect rate such as temperature, concentration, catalysts, and surface area. It also discusses reversible and irreversible reactions, chemical equilibrium, and factors that affect equilibrium like temperature, pressure, and concentration. Finally, it defines exothermic and endothermic reactions, and uses energy level diagrams to illustrate the differences.
1. The document outlines a secondary school chemistry programme covering rates of reaction.
2. It discusses how factors like concentration, temperature, and surface area affect the rate of reactions. Experiments are described to investigate these effects.
3. The programme covers topics over 5 weeks, including graphical interpretation of rate data, exothermic and endothermic reactions, heat of reactions, and an energetics review. Lessons provide definitions, explanations, worksheets, and balanced equations.
The document discusses various topics related to chemical kinetics including:
- Definitions of rate of reaction, instantaneous rate, and average rate.
- Integrated rate equations for zero-order and first-order reactions and how to determine the half-life of a first-order reaction from its rate constant.
- The Arrhenius equation and how it relates the temperature dependence of reaction rates to activation energy. Increasing temperature increases the fraction of molecules with energy exceeding the activation energy.
- How catalysts increase reaction rates by providing an alternative reaction pathway requiring lower activation energy.
Rate of reaction for limestone and citric acid.dhmcmillan
The document describes an experiment to measure the rate of reaction between calcium carbonate and citric acid. Calcium carbonate and citric acid react to produce calcium citrate, carbon dioxide gas, and water. The rate of reaction is measured by determining the volume of carbon dioxide gas produced over time as it is a product of the reaction. The results are recorded in a table showing the volume of carbon dioxide detected after various time intervals. These results can then be used to calculate values like the rate of reaction and number of moles of carbon dioxide produced.
The document discusses kinetics and reaction rates. It defines kinetics as the study of reaction rates, and explains that thermodynamics determines if a reaction will occur but not how fast. It then covers factors that affect reaction rates like temperature, concentration, and catalysts. The document provides examples of calculating rates from concentration data and determining rate laws from experimental results. It also introduces integrated rate laws and how to determine reaction order from different rate law equations.
The document summarizes an experiment investigating the effect of concentration and temperature on the rate of a Harcourt-Essen reaction. By varying the concentration of iodide ions between runs, the reaction was found to be second order overall and first order with respect to both peroxide ions and iodide ions. Increasing the temperature between runs caused the rate coefficient to increase, demonstrating that the reaction rate increases with temperature in accordance with the Arrhenius equation.
This document discusses chemical kinetics and reaction rates. It begins with an introduction to chemical kinetics and defines reaction rate. It then discusses factors that affect reaction rates such as nature of reactants, concentration, temperature, and catalysts. It describes different types of reaction rates and how they are measured. The document also covers rate laws, determining rate orders experimentally, and integrated and differential rate equations for zero, first, and second order reactions. It concludes with an overview of rate theories including the Arrhenius equation.
1. Photosynthesis converts sunlight into chemical energy through two stages - the light-dependent reactions which produce ATP and NADPH using chlorophyll, and the light-independent Calvin cycle which uses these products to fix carbon and produce glucose.
2. The light-dependent reactions take place in the thylakoid membranes of the chloroplast and involve the absorption of light by photosystems and electron transport chains to generate a proton gradient for ATP synthesis via chemiosmosis.
3. The light-independent Calvin cycle occurs in the chloroplast stroma and uses the ATP and NADPH from the light reactions to reduce carbon dioxide and produce glucose through a series of reduction
1. Photosynthesis converts sunlight into chemical energy through light-dependent and light-independent reactions. 2. The light-dependent reactions use sunlight to produce ATP and NADPH through electron transport. 3. The light-independent Calvin cycle uses ATP and NADPH to fix carbon from CO2 into organic three-carbon sugars like G3P.
The document discusses activities of integration, which are assessments that evaluate students' ability to solve problems by integrating knowledge from a chapter. It provides examples of activities of integration, such as writing a letter inviting teachers to an end-of-year party. It also discusses the components of activities of integration, such as the problem/scenario and expected output. Additionally, it covers how to develop an assessment grid to score activities of integration based on relevance, accuracy, coherence and excellence. Teachers are then instructed to work in groups to create an activity of integration for any S1 topic along with its corresponding assessment grid.
This document provides guidance on managing large classes in competency-based education. By the end of the session, participants will explore the concept of large classes in competency-based education and elicit hands-on strategies for managing them. The document aims to help participants understand what constitutes a large class, ensure learning outcomes are achieved for all students in large classes, and provide subject group activities to discuss best practices.
Biostatistics uses statistical methods to analyze biological data, especially related to health and medicine. It is used widely in areas like public health, cancer research, pharmacology, ecology, genetics, and more. Some key uses of biostatistics include testing hypotheses, interpreting experimental results, determining treatment effectiveness, examining disease trends, and predicting outcomes. Proper use of biostatistical methods helps biologists design experiments, analyze results, and draw valid conclusions from their research.
Sulphur dioxide can be prepared in the laboratory by adding dilute sulphuric acid to sodium sulphite. This produces sulphur dioxide gas along with sodium sulphate and water. Sulphur dioxide can be detected using acidified potassium dichromate solution, which turns from orange to green upon reaction. Excess sulphur dioxide bubbled through sodium hydroxide forms sodium hydrogen sulphite. Sulphur dioxide is used to manufacture sulphuric acid via the contact process, where it is oxidized to sulphur trioxide and absorbed in concentrated sulphuric acid.
Chlorine and its compounds are discussed. Chlorine can be prepared in the laboratory by reacting concentrated hydrochloric acid with manganese(IV) oxide or potassium manganate(VII). Chlorine is a greenish-yellow gas that is denser than air and acts as a strong oxidizing agent and bleach. It reacts with many metals and non-metals to form chlorides. Common uses of chlorine include water disinfection and manufacturing of bleaches, plastics and pesticides.
This document discusses taxonomy and binomial nomenclature. It defines taxonomy as the science of identifying and classifying organisms, and notes that over 1.7 million species have been described. Binomial nomenclature, introduced by Carolus Linnaeus in 1758, assigns every species a two-part scientific name - the genus followed by a specific epithet. This standardized naming system ensures organisms have unique, unambiguous Latinized names. International codes govern naming conventions for different taxonomic groups like plants, animals and viruses.
The document summarizes key aspects of photosynthesis, including:
- Photosynthesis occurs in chloroplasts within plant cells and involves the absorption of light energy by chlorophyll to convert carbon dioxide and water into glucose and oxygen.
- Chlorophyll is the primary photosynthetic pigment that absorbs light in the blue and red wavelengths while reflecting green light, giving plants their green color.
- Other pigments like carotenoids help capture a broader range of wavelengths and transfer energy to chlorophyll.
- The light-dependent and light-independent reactions of photosynthesis utilize the energy from light absorption to fix carbon into sugars.
This document discusses nutrition and balanced diets. It defines the three main functions of food as energy-yielding, body-building, and protective. It explains the three food groups and emphasizes the importance of a varied, balanced diet containing portions from each group. Key nutrients like proteins, fats, carbohydrates, vitamins, minerals, antioxidants and their major food sources are outlined. The biological value and quality of different protein sources is also summarized.
This document discusses food and nutrients. It defines food as any substance that can provide nutrients to the body. Nutrients are chemical substances that help the body stay healthy and energetic. There are five main types of nutrients: carbohydrates, proteins, fats, vitamins, and mineral salts. Carbohydrates, proteins and fats provide energy, while all nutrients have roles in growth, repair, and regulation of functions. A balanced diet containing all nutrients is essential for health.
The document describes the Kingdom Monera, which consists mainly of eubacteria and cyanobacteria. Eubacteria are heterotrophic organisms that are named according to their shape, such as coccus (round), spirillum (spiral), and bacillus (rod-shaped). Cyanobacteria are autotrophic organisms commonly found in aquatic and terrestrial environments; they can exist as unicellular, colonial, or filamentous forms, and some can fix nitrogen through specialized cells called heterocysts.
Genetic disorders and diseases are caused by mutations in genetic material that can be inherited from parents or caused by environmental factors like radiation or chemicals. Mutations can occur when whole chromosomes are missing or extra chromosomes are present, or when sections of chromosomes are missing or in the wrong place. Examples of genetic disorders include Down syndrome, which results from an extra copy of chromosome 21, and sickle cell disease, phenylketonuria, Tay-Sachs disease, cystic fibrosis, and Huntington's disease, which are caused by recessive defective alleles inherited from both parents.
This document provides guidance on managing large classes in competency-based education. By the end of the session, participants will explore the concept of large classes in competency-based education and elicit hands-on strategies for managing them. The document aims to help participants understand what constitutes a large class, ensure learning outcomes are achieved for all students in large classes, and provide subject group activities to discuss best practices.
Methodologies and techniques to teach new curriculum in.pptxBagalanaSteven
This document outlines various methodologies and techniques that can be used to teach a new entrepreneurship curriculum in lower secondary schools. It discusses learner-centered teaching methods like discussion, case studies, brainstorming, buzz groups, demonstrations, guest speakers, role-playing, guided discovery, field trips and attachments. It also covers factors to consider when choosing a methodology, like the competencies being taught, available aids, learner age and interests. Techniques discussed for teaching the new curriculum include using simplified materials, integrating old content, avoiding duplication, using local examples, videos, engaging learners, fieldwork and ensuring timely coverage.
The document provides information about internet services and protocols. It defines common internet services like the World Wide Web, email, file transfer protocol, newsgroups, chat rooms and video conferencing. It describes how to use email by outlining features such as To, CC, BCC, attachments and address formats. Internet protocols discussed include TCP/IP, HTTP, FTP, SMTP, POP3 and IMAP. The document also defines common terms related to using the internet like downloading, uploading, browsing, bookmarks and web servers. Students are instructed to take notes and contact teachers for any clarification needed.
This document discusses learning and assessment through projects. It begins with a KWL activity to understand what teachers know and want to know about projects. Projects empower students to engage with 21st century skills like critical thinking and problem solving. Performance tasks are shorter and more structured, while projects are longer term, interdisciplinary, and focus on real-life issues. Effective projects are based on challenges, require inquiry, and have authentic impact. Projects should be assessed using rubrics that evaluate content, process, quality, and impact. Teachers provide guidance and formative feedback throughout the project process.
This document discusses project-based learning (PBL), a teaching method where students design and carry out an extended project that results in a tangible product or presentation. It is intended to make learning more active and relevant. The key points are:
1) PBL involves students planning and completing a project on a topic of their choice, rather than passively receiving information.
2) Teachers guide students and facilitate learning, while students take responsibility for their own work.
3) Projects incorporate principles like freedom, reality, activity and experience to make learning more meaningful.
4) Successful projects follow steps like planning, execution, documentation and evaluation.
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How to Build a Module in Odoo 17 Using the Scaffold MethodCeline George
Odoo provides an option for creating a module by using a single line command. By using this command the user can make a whole structure of a module. It is very easy for a beginner to make a module. There is no need to make each file manually. This slide will show how to create a module using the scaffold method.
Strategies for Effective Upskilling is a presentation by Chinwendu Peace in a Your Skill Boost Masterclass organisation by the Excellence Foundation for South Sudan on 08th and 09th June 2024 from 1 PM to 3 PM on each day.
This slide is special for master students (MIBS & MIFB) in UUM. Also useful for readers who are interested in the topic of contemporary Islamic banking.
How to Make a Field Mandatory in Odoo 17Celine George
In Odoo, making a field required can be done through both Python code and XML views. When you set the required attribute to True in Python code, it makes the field required across all views where it's used. Conversely, when you set the required attribute in XML views, it makes the field required only in the context of that particular view.
This presentation includes basic of PCOS their pathology and treatment and also Ayurveda correlation of PCOS and Ayurvedic line of treatment mentioned in classics.
1. RATES OF REACTION
RATES OF REACTION
Charles Kidega
St. Gonzaga Budini Sec. Sch.
c.kidega17@gmail.com
+256(0)702816081
2. Kidegalize @Chemistry Archive Network +256(0)702816081
Introduction to rate of reaction
Rate of reaction is the change in the
mass/ concentration/ volume of a given
reactant/ product during the course of
reaction per unit time.
Rate of reaction =
change in amount
change in time
The rate of reaction with respect to
reactant is NEGATIVE because its
amount decreases with time.
3. Kidegalize @Chemistry Archive Network +256(0)702816081
A graph of concentration of reactant
against time
Time(second)
Concentration
(moldm
-3
)
4. Kidegalize @Chemistry Archive Network +256(0)702816081
A graph of concentration of product
against time
Time(second)
Concentration
(moldm
-3
)
5. Kidegalize @Chemistry Archive Network +256(0)702816081
Rate of reaction is inversely
proportional to the time of reaction.
Rate
1
time
Thus a fast reaction takes a short
time and a slow reaction takes a long
time to reach completion.
6. Kidegalize @Chemistry Archive Network +256(0)702816081
Determination of rate of
reaction
The rate of reaction can be determined
by:
(a)Measuring the volume of gaseous
product at different time intervals,
for example:
Mg(s) + 2HCl(aq) MgCl2(aq) + H2(g)
2H2O2(aq) 2H2O(l) + O2(g)
MnO2
7. Kidegalize @Chemistry Archive Network +256(0)702816081
The volume of gas can be measured
using a gas syringe with a frictionless
piston.
For example, Gas syringe
Oxygen
Hydrogen peroxide
Manganese(IV) oxide
8. Kidegalize @Chemistry Archive Network +256(0)702816081
Manganese(IV) oxide is taken in the
flask in the set up of apparatus
shown in the diagram above.
The stopper is opened and hydrogen
peroxide is added onto the
manganese(IV) oxide.
The stopper is quickly fitted back.
Volume of oxygen evolved is measured
from the gas syringe.
9. Kidegalize @Chemistry Archive Network +256(0)702816081
(b) Measuring mass of the reaction
mixture at different time intervals.
This method applies to reactions in
which a gas is given off and it is allowed
to escape. For example,
CaCO3(s) + 2HCl(aq) CaCl2(aq) + CO2(g) + H2O(l)
10. Kidegalize @Chemistry Archive Network +256(0)702816081
Set up of apparatus
Reaction mixture
Bubbles of gas
Cotton wool
Direct weighing
balance
11. Kidegalize @Chemistry Archive Network +256(0)702816081
(c) Measuring the time taken for the
reaction to reach a specific stage.
(i) Time taken for effervescence to
stop e.g.
Mg(s) + 2HCl(aq) MgCl2(aq) + H2(g)
(ii) Time taken to precipitate
sulphur.
S2O3
2 – (aq) + 2H+(aq) S(s) + SO2(g) + H2O(l)
12. Kidegalize @Chemistry Archive Network +256(0)702816081
(iii) Time taken for the brown color to
appear in solution.
H2O2(aq) + 2I – (aq) + 2H+(aq) I2(aq) + 2H2O(l)
13. Kidegalize @Chemistry Archive Network +256(0)702816081
Check Point-1
Question 1
1999/P2/11(a)(i) What is the rate
of reaction? OR
2003/P2/11(a) What is meant by
rate of a chemical reaction? OR
2007/P2/13(a) Define the term rate
of reaction.
14. Kidegalize @Chemistry Archive Network +256(0)702816081
Question 2 (2002/P2/12 )
When a certain volume of 0.1M
hydrochloric acid was reacted at
room temperature with excess of iron
fillings, 120cm3 of a gas were
produced.
(a) Draw a labelled diagram to show
how the rate of reaction was
determined.
15. Kidegalize @Chemistry Archive Network +256(0)702816081
(b) Write equation for the reaction
that took place.
(c) Draw a sketch graph of the volume
of the gas against time.
16. Kidegalize @Chemistry Archive Network +256(0)702816081
Question 3 (1987/P2/7(a) )
A given mass of magnesium strips was
reacted with dilute hydrochloric acid at
room temperature. The volume of the gas
produced was measured at various
intervals.
(i) Write equation for the reaction.
(ii) Sketch a graph to show variations of
the volume of the gas produced with
time.
17. Kidegalize @Chemistry Archive Network +256(0)702816081
Rate curves
A rate curve is a graph obtained when
volume of gas/ concentration of the
reactant/ mass of the reaction
mixture / loss in mass/ temperature
of reaction is plotted against time/
reciprocal of time or vice versa.
To determine the rate of reaction at
any time, t, on the graph:
18. Kidegalize @Chemistry Archive Network +256(0)702816081
• Draw a tangent line at the time
given.
• Complete it to obtain a right-angled
triangle.
• Then calculate the gradient/slope of
the tangent and this is equal to the
rate of reaction at time, t.
19. Kidegalize @Chemistry Archive Network +256(0)702816081
Calculating rate of reaction at time,
t, from the graph
Time(s)
Volume
of
CO
2
(cm
3
)
t
Δt
ΔV
Rate =
ΔV
Δt
cm3s-1
20. Kidegalize @Chemistry Archive Network +256(0)702816081
• To find the volume of a gas/ mass of
reactant/ concentration of reactant
at a given time from the graph, draw
a perpendicular line from the time
axis at the given time, to meet the
curve. Read off the value where the
perpendicular line meets the rate
curve.
21. Kidegalize @Chemistry Archive Network +256(0)702816081
Note
• Show evidence of value obtained
from the graph, use dotted lines or
triangle in case of slope.
• To explain the shape of the graph:
State the relationship and give
reason(s) for the shape.
22. Kidegalize @Chemistry Archive Network +256(0)702816081
• Where necessary, tabulate the rate
of reaction,
1
t
, giving the values in
scientific notation, for example,
0.0068 is recorded as 6.8 × 10–3.
23. Kidegalize @Chemistry Archive Network +256(0)702816081
Checkpoint-2
Question 1
The table below shows the variation in
the concentration of hydrogen
peroxide with time when a sample of
hydrogen peroxide was mixed with
iron(III) chloride at room temperature.
Concentration of S2O3
2-
(M)
0.2 0.6 0.8 1.2 1.6
Time for sulphur to form (s) 60 20 15 10 7.5
1
t
(s-1)
24. Kidegalize @Chemistry Archive Network +256(0)702816081
(a)Copy and complete the table above by
computing and filling in the values of
1
t
(b)Plot a graph of
1
t
against
concentration of hydrogen peroxide.
(c)Using a graph, deduce how the rate of
the reaction varies with the
concentration of hydrogen peroxide.
(d)Determine the slope of the graph.
25. Kidegalize @Chemistry Archive Network +256(0)702816081
Question 2
The table below shows the variation in
volume of hydrogen evolved with time
when dilute hydrochloric acid was
added to excess zinc.
Volume of hydrogen
(cm3)
0 20 35 46 56 72 79 79
Time (s) 0 10 20 30 40 60 80 90
26. Kidegalize @Chemistry Archive Network +256(0)702816081
(a)Plot a graph of volume of hydrogen
evolved against time.
(b)Using the graph, determine the time
taken to collect 60 cm3 of hydrogen
gas.
(c)Draw tangents on your graph at points
when the time is 20 and 60 seconds
and determine the gradient of each
tangent.
(d)Compare the rate of reaction at 20
seconds and 60 seconds.
27. Kidegalize @Chemistry Archive Network +256(0)702816081
Question 3
Dilute hydrochloric acid reacts with
zinc according to the equation.
Zn(s) + 2HCl(aq) ZnCl2(aq) + H2(g)
25cm3 of dilute hydrochloric acid of
different concentration were
separately placed in six beakers. The
same mass of zinc powder was added
to each beaker and the time taken for
effervescence to stop
28. Kidegalize @Chemistry Archive Network +256(0)702816081
was recorded as shown in the table below.
(a)Plot a graph of concentration against
time.
(b) Use the graph to determine the
(i) concentration of hydrochloric acid
Concentration of HCl
(moldm-3)
0.25 0.50 0.75 1.00 1.25 1.50
Time taken(s) 32.0 22.0 14.5 9.5 6.0 3.0
29. Kidegalize @Chemistry Archive Network +256(0)702816081
for which the reaction stops after
10s.
(ii) rate of reaction with 0.50M and
1.25M hydrochloric acid.
(c) Compare the reaction rate in (b)(ii).
Explain your answer.
30. Kidegalize @Chemistry Archive Network +256(0)702816081
Factors affecting rate of
reaction
The factors that affect the rate of
chemical reactions are concentration,
temperature, pressure, catalyst,
surface area and light.
The effect of each factor on the rate
of reaction is explained by the collision
theory which states that chemical
reactions take place when reactant
particles collide.
31. Kidegalize @Chemistry Archive Network +256(0)702816081
Thus rate of reaction is directly
proportional to the number of
collisions per unit time (frequency of
collisions).
• Effect of temperature
The rate of reaction increases with
increase in temperature OR
The higher the temperature, the
faster the rate of a chemical reaction
32. Kidegalize @Chemistry Archive Network +256(0)702816081
At high temperature, more particles
acquire more kinetic energy.
Particles with high kinetic energy
move at increased velocities resulting
into more particles colliding with one
another more frequently and
vigorously. Hence the reaction
proceeds at a faster rate.
33. Kidegalize @Chemistry Archive Network +256(0)702816081
A graph showing volume of gas evolved
against time at different temperatures.
Time(s)
Volume
of
CO
2
(cm
3
)
High Lower
34. Kidegalize @Chemistry Archive Network +256(0)702816081
Note
The curves eventually end at the same
level.
This is because the same mass of
reactant is used and all have been
used up.
35. Kidegalize @Chemistry Archive Network +256(0)702816081
Expt. To show the effect of temperature
on the rate of reaction between sodium
thiosulphate and dilute acid
Standard solutions of thiosulphate and
hydrochloric acid are made.
Equal volumes of thiosulphate solutions
are taken in five different conical flasks.
Temperature of the solution in one of the
conical flasks is recorded and the
36. Kidegalize @Chemistry Archive Network +256(0)702816081
conical flask placed over a cross
marked on a piece of paper on a table.
A known volume of hydrochloric acid is
added and at the same time a stop is
started.
Time taken for the cross to just be
covered is noted.
The procedure is repeated with the
second conical flask heated to a
37. Kidegalize @Chemistry Archive Network +256(0)702816081
temperature slightly above room
temperature. This is done with the
3rd,4th and 5th conical flasks with
temperature in each case higher than
the preceding one.
Graph of temperature against
reciprocal of time is plotted which
gives a straight line. This shows that
rate of reaction increases with
increase in temperature.
38. Kidegalize @Chemistry Archive Network +256(0)702816081
• Effect of concentration of
reactants
The rate of reaction increases with
increase in concentration of
reactants OR
The higher the concentration of
reactants, the faster the rate of
reaction.
39. Kidegalize @Chemistry Archive Network +256(0)702816081
At higher concentration, more particles
are brought together and are close to
each other. Thus the chances of collisions
are higher and more frequent.
For example: when equal masses of
excess magnesium ribbon were
separately reacted with sulphuric acid of
different concentration, different volume
of hydrogen was evolved.
40. Kidegalize @Chemistry Archive Network +256(0)702816081
Graphs showing effect of
concentration on rates of reaction.
(i) Concentration against time
Time(second)
Concentration
(moldm
-3
)
41. Kidegalize @Chemistry Archive Network +256(0)702816081
Initially the concentration of
reactants is high leading to a faster
rate of reaction.
As the reactants get used up, their
concentration decreases and the
rate of reaction slows down since
there are fewer particles colliding
until it finally stops and becomes
constant.
42. Kidegalize @Chemistry Archive Network +256(0)702816081
(ii) Rate against concentration
Concentration(moldm-3)
Rate
of
reaction,
1
time
(s
-1
)
43. Kidegalize @Chemistry Archive Network +256(0)702816081
The graph is a straight line passing
through the origin.
It shows that the rate of reaction is
directly proportional to the
concentration of reactants.
44. Kidegalize @Chemistry Archive Network +256(0)702816081
• Effect of surface area/particle size
The smaller the particle size the
faster the rate of reaction.
Small sized particles e.g. powdered,
provide large surface area on which
reaction can occur. This provides
greater chances for more particles to
participate in the reaction.
45. Kidegalize @Chemistry Archive Network +256(0)702816081
Note
• Surface area affects the rate of
reaction involving solid reactant(s)
only.
• For example, reaction between zinc
and dilute hydrochloric acid shows
that the reaction is faster with
zinc powder than with zinc granules.
46. Kidegalize @Chemistry Archive Network +256(0)702816081
• A reaction between marble chips
(lumps of calcium carbonate) and
dilute hydrochloric acid is slow
compared to that with powdered
calcium carbonate.
47. Kidegalize @Chemistry Archive Network +256(0)702816081
• Thus the rate of reaction is
measured as the rate of change in
mass of the apparatus and its
content.
48. Kidegalize @Chemistry Archive Network +256(0)702816081
A graph of change in mass against
time
X
Y
Time(s)
Mass
of
content(g)
Curve I: Powdered calcium carbonate
Curve II: Marble chips
Z
49. Kidegalize @Chemistry Archive Network +256(0)702816081
In curve I, there is a rapid decrease in
the mass from X to Y due to large
surface area provided by the
powdered calcium carbonate hence
the reaction rate is very fast.
From Y to Z, the mass remains
constant because the reaction has
reached completion.
50. Kidegalize @Chemistry Archive Network +256(0)702816081
In curve II, the mass decreases slowly
and the rate of the reaction is slower
hence less carbon dioxide is produced
and it takes a longer time for the
reaction to reach completion.
This is because of the small surface
area of the marble chips which are in
large lumps.
51. Kidegalize @Chemistry Archive Network +256(0)702816081
A graph of volume of carbon dioxide
evolved against time
Time(s)
Volume
of
CO
2
(cm
3
)
Curve I Curve II
Curve I: Powdered calcium carbonate
Curve II: Marble chips
t1 t2
52. Kidegalize @Chemistry Archive Network +256(0)702816081
In curve I, there is a rapid increase in
the volume of carbon dioxide evolved
due to the large surface area provided
by the powdered calcium carbonate,
hence the reaction rate is very fast
until it reaches its completion and
becomes constant.
53. Kidegalize @Chemistry Archive Network +256(0)702816081
In curve II, there is a gradual increase
in the volume of carbon dioxide
produced and the rate of reaction
slower and it takes a lot of time for
the reaction to reach its completion.
This is because of the smaller surface
area of the marble chips which are in
large lumps.
54. Kidegalize @Chemistry Archive Network +256(0)702816081
Expt. To show how surface area can
affect the rate of the reaction between
calcium carbonate and hydrochloric acid
A given volume of hydrochloric acid of
known concentration is put in a conical
flask and the flask is loosely plugged with
a piece of cotton wool.
The flask with its contents is placed on a
direct weighing balance and the mass
recorded.
55. Kidegalize @Chemistry Archive Network +256(0)702816081
The cotton wool is slightly displaced and
a known mass of lumps of calcium
carbonate is added to the acid and
simultaneously a stop clock is started.
The mass of the flask and its content is
recorded after fixed intervals of time
until there is no further change.
The experiment is repeated using fresh
acid of the same volume and same mass
56. Kidegalize @Chemistry Archive Network +256(0)702816081
of calcium carbonate powder.
The change in mass is due to the carbon
dioxide lost during the reaction.
CaCO3(s) + 2HCl(aq) CaCl2(aq) + CO2(g) + H2O(l)
On the same axes, a graph of mass
against time for the reaction between
the acid and lumps of calcium
carbonate(curve II), the acid and calcium
carbonate powder(curve I)
57. Kidegalize @Chemistry Archive Network +256(0)702816081
is plotted.
The graph shows that the big size of
lumps of calcium carbonate offers a small
surface area for the reaction with
Time(s)
Mass
of
content(g)
58. Kidegalize @Chemistry Archive Network +256(0)702816081
the acid compared to the powdered
calcium carbonate with small sized
particles that offer a large surface
area and the latter reaction reaches
completion in a shorter time.
Therefore, the larger the surface area,
the faster is the rate of reaction.
59. Kidegalize @Chemistry Archive Network +256(0)702816081
• Effect of catalyst
The rate of reaction increases with
addition of a catalyst.
This is because in the presence of a
catalyst, the number of collisions per
unit time increases and the
activation energy is lowered, hence
increased rate of reaction.
60. Kidegalize @Chemistry Archive Network +256(0)702816081
Note
• A catalyst is a substance that alters
the rate of chemical reaction but it
remains chemically unchanged.
• Powdered catalyst are more effective
because the powder presents a large
surface area compared to lumps.
61. Kidegalize @Chemistry Archive Network +256(0)702816081
A graph showing catalysed and
uncatalysed reaction
Time(s)
Volume
of
O
2
(cm
3
)
t
62. Kidegalize @Chemistry Archive Network +256(0)702816081
At any time, t, the volume of oxygen
produced is higher in catalysed
reaction than in uncatalysed
reaction.
63. Kidegalize @Chemistry Archive Network +256(0)702816081
• Effect of pressure
A change in pressure affects
reactions which occur in gaseous
state.
When pressure of a gas mixture is
increased, the gases are compressed
and this brings the gas particles
closer together thus increasing the
frequency of collision between the
reacting particles,
64. Kidegalize @Chemistry Archive Network +256(0)702816081
therefore rate of reaction increases.
Examples of reactions affected by
pressure are:
N2(g) +H2(g) 2NH3(g)
2SO2(g) +O2(g) 2SO3(g)
65. Kidegalize @Chemistry Archive Network +256(0)702816081
• Effect of light
Some reactions are photosensitive.
For example silver chloride darkens
when exposed to light due to its
decomposition to silver metal and
chlorine gas.
2AgCl(s) 2Ag(s) + Cl2(g)
66. Kidegalize @Chemistry Archive Network +256(0)702816081
Checkpoint-3
Question 1 (2013/P2/14)
Sodium thiosulphate reacts with dilute
acids according to the following equation.
(a)State what would be observed if
dilute hydrochloric acid was added to
sodium thiosulphate solution.
(b)The rate of the reaction is affected by
the concentration of sodium
thiosulphate.
(i) State one factor other than
concentration that can affect the
rate of the reaction.
67. Kidegalize @Chemistry Archive Network +256(0)702816081
(ii) Briefly explain the effect of the
factor you have stated in b(i) on the
rate of the reaction.
(iii) Describe an experiment that can be
carried out in the laboratory to show
the effect of the factor you have
stated in b(i) on the rate of the
reaction. (Diagram not required)
68. Kidegalize @Chemistry Archive Network +256(0)702816081
Question 2 (2010/P2/14)
State and explain the effect of each
of the following conditions on the rate
of a chemical reaction.
(a) Particle size.
(b)Concentration of reactants.
(c)Temperature.
69. Kidegalize @Chemistry Archive Network +256(0)702816081
Question 3 (2005/P2/13)
(a) Describe an experiment to show how
surface area can affect the rate of the
reaction between calcium carbonate and
2M hydrochloric acid. Your answer must
include:
a labelled diagram of the apparatus.
sketch of expected graphs.
mention of how the graphs can be used to
make conclusions.
70. Kidegalize @Chemistry Archive Network +256(0)702816081
(b) Briefly explain why, when a 4M
hydrochloric acid was used instead of
2M acid, the rate of the reaction was
faster. Explain the observation.
(c) State one factor other than those
mentioned above that can affect the
rate of the reaction between
hydrochloric acid and calcium chloride.