Course Content
Matter
OBJECTIVES By the end of this topic, the trainee should be able to 1.Define matter 2.Explain state of matter 3.Distinguish between physical and chemical changes 4.Explain the gas laws
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Atoms , Elements and Compounds
OBJECTIVES By the end of this topic , the trainee should be able to; 1.Define Elements, Compounds and Mixtures 2.Describe the structure of an atom 3.Describe how to determine the Atomic number ,Mass number and Isotopes
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The Periodic Table
OBECTIVES By the end of this topic, the trainee should be able to : 1.State the historical contribution on development of the periodic table 2.Explain the periodic trends of elements and their compounds 3.State the diagonal relationships of the periodic table
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The S-Block Element
OBJECTIVES By the end of this topic, the trainee should be able to: 1.Explain the chemistry of group I and II elements 2.State the application of group I and two elements and their compounds
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Chemical Bonds
OBJECTIVES By the end of these topic, the trainee should be able to 1.Identify different types of bonds 2.Describe their properties
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Chemical Equilibrium
OBJECTIVES By the end of this topic , the trainee should be able to : 1.Define chemical equilibria 2.Explain types of equilibria 3.Determine equilibrium constant 4.Describe factors affecting chemical equilibrium
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Introduction To Organic Chemistry
By the end of this topic , the trainee should be able to : 1.Explain the aspects of organic chemistry 2.Describe hydrocarbons 3.Classify organic molecules explain chemical reactions of simple organic molecules 4.Explain the properties , synthesis and uses of simple organic molecules
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Acids, Bases and Salts
OBJECTIVES By the end of this session , the trainee should be able to : 1.State properties of acids and bases 2.Differentiate between strong and weak acids 3.Explain types and properties of salts
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PH Analysis
OBJECTIVES By the end of this topic, the trainee should be able to: 1.Define the term PH 2.Explain the basic theory of PH 3.State the relationship between PH and color change in indicators 4.Explain the term buffer solution 5.Describe the preparation of buffer solutions 6.State the application of buffer solutions
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Sampling and Sample Preparation
OBJECTIVE By the end of this topic, the trainee should be able to : 1.Define the terms used in sample preparation 2.State the importance of sampling 3.Describe the techniques of sampling 4.Describe the procedure for sample pre-treatment 5.State sample storage methods
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Separation Techniques
OBJECTIVES By the end of this topic , the trainee should be able to : 1.Define separation, extraction and purification 2.Describe the separation , extraction and purification techniques 3.Explain the methods of determining purity of substances
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Heating and Cooling Techniques
OBJECTIVES To identify various techniques used for heating and cooling substances in the laboratory
Heating and Cooling Techniques
OBJECTIVES To identify various techniques used for heating and cooling substances in the laboratory
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Distillation Techniques
By end of this topic, Trainee should be able to : 1. Define distilation 2. State and explain various distillation techniques 3. Outline Various distillation techniques 4. Outline the applications of Distillation techniques
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Crystallization Techniques
OBJECTIVES By the end of the topic, the learner should be able to: 1.To define crystallization 2.To describe crystallization process 3.To carry out crystallization procedure
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Solvent Extraction Techniques
OBJECTIVES By the end of the topic, the learner should be able to 1.Define solvent extraction 2.Explain terms used in solvent extraction 3.Describe methods of solvent extraction 4.Describe selection of appropriate solvents for solvent extraction 5.Determine distribution ration 6.Outline factors actors influencing the extraction efficiency 7.Describe Soxhlet extraction
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Chromatography Techniques
OBJECTIVES By the end of this topic, the learner should be able to: 1.Define chromatography techniques 2.Explain terms used in chromatography techniques 3.Describe principles of chromatography techniques 4.Explain types of chromatography techniques 5.Carry out chromatography experiments 6.Determine RF factor 7.Outline electrophoresis
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Titrimetric Analysis
OBJECTIVES By the end of this topic, the trainee should be able to: 1.Define terms used in titrimetric analysis 2.Describe types of titrimetric analysis 3.Balance chemical reactions 4.Work out calculations involved in titrimetric analysis
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Redox Titration
Redox Titration is a laboratory method of determining the concentration of a given analyte by causing a redox reaction between the titrant and the analyte. Redox titration is based on an oxidation-reduction reaction between the titrant and the analyte. It is one of the most common laboratory methods used to identify the concentration of unknown analytes. Redox reactions involve both oxidation and reduction. The key features of reduction and oxidation are discussed below.
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Complexiometric Titration
omplexometric Titration or chelatometry is a type of volumetric analysis wherein the colored complex is used to determine the endpoint of the titration. The method is particularly useful for determination of the exact number of a mixture of different metal ions, especially calcium and magnesium ions present in water in solution .
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Gravimetric Analysis
OBJECTIVES By the end of this topic, the trainee should be able to: 1.Define gravimetric analysis 2.Describe the principles of gravimetric analysis 3.Describe the steps involved in gravimetric analysis 4.Explain factors affecting gravimetric analysis 5.Describe the equipments and apparatus used in gravimetric analysis 6.Carry out gravimetric analysis
0/8
Calorimetric Analysis
OBJECTIVES By the end of this topic, the trainee should be able to: 1.Define terms and units used in thermochemistry 2.Determine enthalpy changes in chemical reactions 3.Determine heat capacity and specific heat capacity 4.Compare calorific values of different materials 5.Determine different heat reactions 6.Apply law of conservation of energy and Hess law in thermochemical calculations
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Chemistry Techniques for Science Laboratory Technicians
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EDTA Complexometric Titration

EDTA (ethylenediaminetetraacetic acid) titration is a common technique used in analytical chemistry to determine the concentration of metal ions in a solution. EDTA is a chelating agent that forms stable complexes with metal ions, and the titration involves the use of a standardized EDTA solution to react with the metal ions present in the sample.

EDTA is a complexometric indicator consisting of 2 amino groups and four carboxyl groups called as Lewis bases . 

 Before using it, it is  converted into sodium salts that are feasible in water. Since it is  characterised with less solubility in water, it is  used for titration.

Principle of Complexometric Titration:

The principle of EDTA (ethylenediaminetetraacetic acid) titration is based on the formation of stable complexes between metal ions and EDTA. EDTA is a chelating agent that has a strong affinity for metal ions, particularly those with transition metals.

The principle can be summarized as follows:

  1. Formation of metal-EDTA complexes: In an aqueous solution, EDTA exists as a hexadentate ligand, meaning it has six donor atoms available for coordination with metal ions. These donor atoms are the four oxygen atoms and two nitrogen atoms of the EDTA molecule. When EDTA is added to a solution containing metal ions, the metal ions coordinate with the EDTA molecules, forming metal-EDTA complexes.

  2. Stoichiometry of the reaction: The formation of metal-EDTA complexes follows a 1:1 stoichiometry, meaning one metal ion reacts with one EDTA molecule to form a complex. The reaction is typically represented as follows:

    Metal ion + EDTA ⇌ Metal-EDTA complex

    The stability of the metal-EDTA complex depends on the specific metal ion and the pH of the solution.

  3. Endpoint determination: During the EDTA titration, a suitable indicator is added to the solution. The indicator undergoes a color change when the metal ions form complexes with EDTA. The choice of indicator depends on the specific metal ion being analyzed. For example, Eriochrome Black T (EBT) is commonly used for titrations involving calcium ions, while Murexide or Calmagite is used for titrations involving magnesium ions.

  4. Titration process: The sample solution containing the metal ion of interest is titrated with a standardized EDTA solution. The EDTA solution is slowly added from a burette to the sample solution while stirring continuously. As the EDTA reacts with the metal ions in the sample, the metal-EDTA complexes form, leading to the color change of the indicator.

  5. Endpoint determination and calculation: The endpoint of the titration is reached when all the metal ions in the sample have reacted with the EDTA. The color change of the indicator indicates the endpoint. The volume of the EDTA solution used in the titration is recorded. Based on the stoichiometry of the reaction and the volume of the EDTA solution used, the concentration of the metal ions in the original sample can be calculated.

The principle of EDTA titration allows for the quantitative determination of various metal ions in a sample. The stability of the metal-EDTA complex and the choice of indicator play crucial roles in achieving accurate and precise results. This technique is widely used in analytical chemistry for determining the concentration of metal ions in various samples, such as water, food, pharmaceuticals, and environmental samples.

Here is a general outline of the EDTA titration process:

  1. Preparation of the sample: The sample containing the metal ion of interest is typically dissolved in a suitable solvent. If necessary, the sample may undergo pre-treatment steps such as dilution, filtration, or digestion to ensure accurate analysis.

  2. Standardization of the EDTA solution: The EDTA solution is prepared and standardized using a primary standard compound, such as calcium carbonate (CaCO3) or zinc. The primary standard is weighed accurately and dissolved to form a known concentration solution. This standardized EDTA solution is then used for the titration.

  3. Titration setup: A known volume of the sample solution is transferred into a titration flask or beaker. If necessary, the pH of the solution is adjusted to a specific range using a buffer solution. A suitable indicator is added to the solution, which undergoes a color change when the metal ions form complexes with EDTA.

  4. Titration process: The standardized EDTA solution is added slowly from a burette into the sample solution while stirring continuously. The EDTA forms complexes with the metal ions present in the solution. As the titration proceeds, the color of the indicator changes, indicating the endpoint of the reaction.

  5. Endpoint determination: The endpoint of the titration is typically indicated by a color change of the indicator. The choice of indicator depends on the specific metal ions being analyzed. Common indicators used in EDTA titrations include Eriochrome Black T (EBT), Murexide, or Calmagite.

  6. Calculation of results: The volume of EDTA solution used in the titration is recorded. Using stoichiometry, the concentration of the metal ions in the sample can be determined based on the balanced chemical equation of the reaction. The concentration of the metal ion in the original sample is calculated using the volume of the sample and the volume of the EDTA solution used.

EDTA titration is a versatile method and can be used to determine the concentration of various metal ions, such as calcium, magnesium, zinc, iron, copper, and many others. The technique allows for accurate and precise quantification of metal ions in a wide range of samples, including water, food, pharmaceuticals, and environmental samples.

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