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
0/6
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
About Lesson

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 EDTA titration experiment 

Solutions Needed 

EDTA: (ethylenediaminetetraaceticacid) 

500 mL of a 0.05 molL-1 solution. 

Weigh 9.31 g of the EDTA salt and dissolve it in 500 mL of distilled water in a volumetric flask.

Buffer: Dissolve 7.0 g of ammonium chloride in 57 mL concentrated ammonia (for safety reasons).

Dilute to 100mL with distilled water in a volumetric flask. The pH should be 10.5. MgCl2 .6H2 O: 0.025 molL-1 solution.

 Weigh 2.54 g of magnesium chloride hexahydrate and dilute to 500 mL with distilled water in a volumetric flask. 

ErioT indicator: Dissolve 0.2 g of Eriochrome Black T indicator in 15 mL of concentrated ammonia solution (or 15 mL of triethanolamine) and 5mL absolute ethanol. Do not store more than one to two days before use. 

Sample Preparation

 For samples that are already in solution, such as freshwater, seawater and milk, no further preparation is needed. 

  1. For solid samples such as eggshells and limestone, the samples must first be dissolved in acid

Accurately weigh about 0.5 g of the solid into a small beaker or conical flask, add about 20 mL dilute hydrochloric acid and allow the solid to completely dissolve (this may take several minutes). 

  1. Neutralise the unreacted acid with dilute sodium hydroxide solution until the pH of the solution is almost 7 (according to pH indicator paper). 
  2. For eggshells, the inner membrane will remain undissolved and may be carefully removed from the solution. 
  3. Transfer the solution to a 100 mL volumetric flask and make up to the mark with distilled water.

Standardisation of the EDTA Solution 

  1. Pipette a 10 mL sample of the EDTA solution into a conical flask. 
  2. Add 10 mL of ammonia buffer solution and 1 mL of Eriochrome Black T indicator solution. 
  3. Titrate the EDTA with the magnesium chloride solution until the endpoint is reached – a permanent colour change from blue to pink. 
  4. Having determined the average titre of the magnesium chloride solution, determine the number of moles used
  5. given the Mg+2and EDTA ratio is 1:1, Calculate the concentration of your EDTA solution 

Titration Method for Seawater, Milk and Solid Samples 

  1. Pipette 10 mL of the sample solution into a conical flask. 
  2. Add 20 mL of 0.05 mol L−1 EDTA solution. 
  3. Add 10 mL of ammonia buffer, 50 mL of distilled water and 1 mL of Eriochrome Black T indicator solution. 
  4. Titrate the sample with the standard 0.025 molL−1 magnesium chloride solution until a permanent pink colour appears

Titration Method for Fresh or Tap Water Samples 

  1. Add a 100 mL of the sample solution into a 250 mL conical flask. 2. Prepare a 0.005 mol L−1 EDTA solution by diluting the 0.05 mol L−1 EDTA solution by a factor of 1/10. Add 20mL of this diluted EDTA to the sample solution. 
  2. Add 10 mL of the ammonia buffer and 1 mL of Eriochrome Black T indicator solution. 
  3. Prepare a 0.0025 mol L−1 magnesium chloride solution by diluting the 0.025 mol L−1 magnesium chloride solution by a factor of 1/10. 

 Titrate the sample solution with this 0.0025 molL−1 magnesium chloride solution until a permanent pink colour appears. 

Repeat the titration with further samples until concordant results (titres agreeing within 0.1 mL) are obtained.

Result Calculations 

  1. Calculate the total moles of EDTA added to the sample solution. 
  2. Calculate the moles of the magnesium chloride solution used in the back titration from your concordant results. From the equation of the titration below, the moles of Mg2+will be equivalent to the moles of excess EDTA. 

                     EDTA4− + Mg2+ → [Mg-EDTA]2− 

  1. Given the ratio of Ca2++ Mg2+: EDTA = 1 : 1, calculate the moles of Ca2+ and Mg2+ that must have been complexed with EDTA by subtracting the excess EDTA from the total moles of EDTA added to the sample. This result is the moles of Ca2+ and Mg2+ in the sample solution.
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