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
0/4
Introduction
States of Matter
Physical and Chemical Properties and Changes
The Gas Laws
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
0/3
Introduction
Atomic Structure
Atomic Structure of Isotopes
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
0/3
Introduction
Families of the Periodic Table
The Periodic Trends
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
0/4
Introduction
Electronic Configuration of S-Block Elements
Physical Properties of S-Block Elements
Chemical Properties of S-Block Elements
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
0/2
Introduction
Types and Properties of Chemical Bonds
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
0/6
Introduction
Measuring Equilibrium Rates
Equilibrium Basics
Types of equilibria
Predicting The Direction of a Reaction
Factors Affecting equilibrium
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
0/10
Introduction
Functional Groups
Alkanes
Alkenes and Alkynes
Alkanols(Alcohols)
HaloAlkanes
Alkanals and Alkanones
Carboxylic Acids
Esters
Amines
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
0/2
Introduction
Properties Of Acids And Bases
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
0/5
Introduction
Neutral, acidic and basic solutions
PH and Its Importance
Determination Of PH
Buffer Solutions
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
0/5
Introduction
Types of Samples and Sampling
Sample preparation
Sample Losses During Preparation
Sample Identification and Storage
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
0/2
Introduction
Separation Techniques
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
0/1
Heating and Cooling Techniques used in the lab
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
0/3
Introduction
Types of Distillation Techniques 
Distillation and Reflux Condensers
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
0/1
Crystallization Technique
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
0/1
Introduction
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
0/6
Introduction to Chromatography Techniques
Types of Chromatography Techniques
Thin Layer Chromatography
Column Chromatography
Retardation Factor (Rf)
Gas-Liquid Chromatography
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
Introduction
Requirements For Titrimetric Analysis
Titration procedure:
Molarity
Apparatus for titrimetric analysis
Classification Of Reactions In Titrimetrlc Analysis
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.
0/5
Introduction
The oxidation number 
Balancing Redox Reactions
Examples Of Redox Titration
Standardization of Redox solutions
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 .
0/5
Introduction to Complexiometric Titration
EDTA titration
Types of EDTA titrations
EDTA titration experiment 
Mechanism of action of indicator:
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
Introduction
Principles Of Gravimetric Analysis
Determination of Mass in gravimetric analysis
Factors Affecting Separation Of Metals And Compounds
Preparation of pure precipitates
Example of gravimetric Analysis
Gravimetric Calculations
Draft Lesson
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
0/4
Introduction
Calorimetry
Heat Capacity
Enthalpy of Phase Transitions
Chemistry Techniques for Science Laboratory Technicians
About Lesson

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Principles Of Gravimetric Analysis

In precipitation gravimetry, the analyte is converted to a sparingly soluble precipitate. This precipitate is then filtered, washed free of impurities, converted to a product of known composition by suitable heat treatment, and weighed. For example, a precipitation method for determining calcium in natural waters involves the addition of C2O42- as a precipitating agent :

                        Ca2+ (aq) + C2O42- (aq)    →    CaC2O4 (s)

The precipitate CaC2O4 is filtered, then dried and ignited to convert it entirely to calcium oxide:

                     CaC2O4 (s)       →      CaO (s) + CO (g) + CO2(g)

After cooling, the precipitate is weighed, and the calcium content of the sample is then computed.

Steps In Gravimetric Analysis

  1. Preparation of the Solution:

This may involve several steps including adjustment of the pH of the solution in order for the precipitate to occur quantitatively and get a precipitate of desired properties, removing interferences etc.

  1. Precipitation:

This requires addition of a precipitating agent solution to the sample solution. Upon addition of the first drops of the precipitating agent, supersaturation occurs, then nucleation starts to occur where every few molecules of precipitate aggregate together forming a nucleus.

 At this point, addition of extra precipitating agent will either form new nuclei (  precipitate with small particles  ) or will build up on existing nuclei to give a precipitate with large particles .  The following factors determine a successful analysis by precipitation.

  1. The precipitate must be so insoluble that no appreciable loss occurs when it is collected by filtration. In practice this usually means that the quantity remaining in solution does not exceed the minimum detectable by the ordinary analytical balance, viz. 0.1 mg.
  2. The physical nature of the precipitate must be such that it can be readily separated from the solution by filtration, and can be washed free of soluble impurities. These conditions require that the particles are of such size that they do not pass through the filtering medium, and that the particle size is unaffected (or, at least, not diminished) by the washing process.
  3. The precipitate must be convertible into a pure substance of definite chemical composition; this may be effected either by ignition or by a simple chemical operation, such as evaporation, with a suitable liquid.
  4. .Digestion of the Precipitate:

The precipitate is left hot (below boiling) for 30 min to 1 hour in order for the particles to be digested. Digestion involves dissolution of small particles and reprecipitation on larger ones resulting in particle growth and better precipitate characteristics.

This process is called Ostwald ripening. An important advantage of digestion is observed for colloidal precipitates where large amounts of adsorbed ions cover the huge area of the precipitate.

Digestion forces the small colloidal particles to agglomerate which decreases their surface area and thus adsorption.  

The precipitate often contains ions that where trapped when the precipitate was formed. This is mostly a problem for crystalline precipitates. If the trapped ions are not volatile, then their presence will corrupt the weighing step. Concentration of interfering species may be reduced by digestion. Unfortunately ,postprecipitation  as we will see later will increase during digestion.

  1. 4. Washing and Filtering

Problems with  surface adsorption may be reduced by careful washing of the precipitate. With some precipitates, peptization occurs during washing. Each particle of the precipitate has two layers , in primary layer certain ions are adsorbed and in the outer layer other ions of opposite charge are adsorbed . This situation makes the precipitate settle down .

 If the outer layer ions are removed then all the particles will have the same charge so the particles will be dissonant . This is called peptization .This results in the loss of part of the precipitate because the colloidal form may pass through on filtration. ,

 in case of colloidal precipitates we should not use water as a washing solution since peptization would occur. In such situations dilute volatile electrolyte such as  nitric acid, ammonium nitrate, or dilute acetic acid may be used.  

Usually, it is a good practice to check for the presence of precipitating agent in the filtrate of the final washing solution. The presence of precipitating agent means that extra washing is required.

 Filtration should be done in appropriate sized Gooch or ignition ashless filter paper. After the solution has been filtered, it should be tested to make sure that the analyte has been completely precipitated. This is easily done by adding a few drops of the precipitating reagent to the filtrate ; if a precipitate is observed, the precipitation is incomplete.

5- Drying and Ignition:

The purpose of drying (heating at about 120-150 oC in an oven) is to remove the remaining moisture while the purpose of ignition in a muffle furnace at temperatures ranging from 600-1200 oC is to get a material with exactly known chemical structure so that the amount of analyte can be accurately determined .

The precipitate is converted to a more chemically stable form. For instance, calcium ion might be precipitated  using oxalate ion, to produce calcium oxalate (CaC2O4) which is hydrophil , therefore it is better to be heated to convert it into  CaCO3  or CaO . The CaCO3 formula is preferred to reduce weighing errors.

6-Weighing the precipitate :

The precipitate can not be weighed with the necessary accuracy in place on the filter paper; nor can the precipitate be completely removed from the filter paper in order to weigh it.The precipitate can be carefully heated in a crucible until the filter paper has burned away; this leaves only the precipitate. (As the name suggests, “ashless” paper is used so that the precipitate is not contaminated with ash.)

 . If you use Gooch crucible then after the precipitate is allowed to cool (preferably in a desicator to keep it from absorbing moisture), it is weighed (in the crucible).  The mass of the crucible is subtracted from the combined mass, giving the mass of the precipitated analyte. Since the composition of the precipitate is known, it is simple to calculate the mass of analyte in the original sample.

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