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Showing posts from May, 2023

Full CBT Rollout for SSCE Postponed to 2027 by WAEC

 Abuja — The West African Examinations Council (WAEC) has postponed the full implementation of the computer-based test (CBT) format for the 2026 Senior School Certificate Examination (SSCE) until 2027, according to a statement released at the council’s 63rd annual meeting in Umuahia, Abia State.  Hajia Binta Abdulkadir, Chairman of WAEC’s Nigeria National Committee, explained that the 2026 May/June edition will now serve as a pilot phase — allowing candidates to sit for either the traditional paper-and-pen test or the digital format. She emphasized that no student will be disadvantaged by the transition.  The delay follows widespread concern over the readiness of many schools, particularly in rural areas, for full digital exams. Many institutions lack adequate computers, reliable electricity, internet connectivity, and trained personnel—factors WAEC and the Federal Ministry of Education say are essential for a successful rollout.  To facilitate the switch, WAEC co...

How to calculate Limiting and Excess Reagents

The calculation of limiting reagents and excess reagents is a real-life application of the stoichiometric relationship between reactants and products. Limiting Reagent : this is the reagent which gets consumed entirely in the chemical reaction. It determines how long a chemical reaction will last or the amount of products to be produced. In other words, the limiting reagent or reactant stops the chemical reaction.  Excess Reagent : this is the reactant that could continue to react if the other reactant is still available for the reaction.  Let us look at this example, and assume that all the requirements of producing a tricycle are three wheels and a wheel steering and a tricycle company has 600 wheels and 250 wheel-steerings for the production of tricycles. Which of the materials will finish first and how many of the other materials will be left over?       3 wheels + 1 steering = 1tricycle The first thing to do is to find the number of tricycles th...

2023 WAEC Possible Volumetric Analysis

  B is a solution of Na 2 CO 3 . nH 2 O prepared by dissolving 5.0g of the hydrated salt in 350cm 3 of solution. A is a solution containing 0.1 moles of hydrochloric acid per dm 3 of solution. a)       Put A into the burette and titrate 20 or 25cm 3 portions of B using methyl orange as an indicator. Record the volume of your pipette. Tabulate your reading and calculate the average volume of acid used. b)       From your results and information given, calculate the i)                     Concentration of B in mole per dm 3 ii)                    Value of Na 2 CO 3 . nH 2 O iii)                  Percentage of water of crystallisation The equation of reaction...

Possible WAEC 2023 Chemistry Practical Salt Analysis

  There are two samples of compounds to be examined in this coming examination: zinc oxide and glucose. Glucose is tagged C n and zinc oxide is tagged D n .    Glucose is an example of a monosaccharide. It is a strong reducing agent because of the presence of the –CHO group. It is dehydrated to carbon by concentrated tetraoxosulphate (VI) acid like all other carbohydrates.   Zinc oxide is a white insoluble powder which turns yellow when it is hot. As an amphoteric oxide, it can dissolve in both acids and alkalis. Analysis of Glucose The reducing property of glucose can be identified by the following experiments: ·          Its reaction with acidified potassium tetraoxomanganate (VII) solution. Glucose decolorizes acidified potassium tetraoxomanganate (VII) solution from purple to colourless. ·          Its reaction with acidified potassium heptaoxodichromate (VI) solution. ...

WAEC 2023 Chemistry and Biology specimens

    CHEMISTRY SPECIMEN  In addition to the fitting and reagents normally found in a chemistry laboratory, the following apparatus and materials will be required by each candidate: a)       One burette of 50cm 3 capacity b)       One pipette either 20cm 3 or 25cm 3 ( All candidates at one centre must use  pipette of the same volume. These should be clean and free from grease) c)        The usual apparatus for titration d)       The usual apparatus and reagents for qualitative work including the following with all reagents appropriately labelled                                 I.             Dilute sodium hydroxide solution   ...