WASSCE Candidates’ Weaknesses In Chemistry And Remedies | Extract From Chief Examiners Report Towards WASSCE 2023 Chemistry

WASSCE Candidates’ Weaknesses In Chemistry And Remedies | Extract From Chief Examiners Report Towards WASSCE 2023 Chemistry

Teachers preparing students for any examination are always worried about the potential weaknesses in answers that their students will provide during the examination. Fortunately, the main examining body, the West Africa Examination Council always provide WASSCE candidates’ weaknesses in Chemistry during the last held examinations.

WAEC Summary of 2021 WASSCE Chemistry Paper Two (2)

A. SUMMARY OF CANDIDATES’ STRENGTHS

The responses given by the candidates that need commendations are:

(1) ability to distinguish between atomic mass and atomic number;

(2) calculation of volume of a gas at s.t.p given other conditions of temperature, pressure and volume it occupied;

(3) distinction between structural formula and empirical formula;

(4) what valency is, and the laws of chemical combination especially “law of conservation of matter”;

(5) liquid fractions obtained from the fractional distillation of petroleum;

(6) writing of electron configuration given atomic numbers;

(7) use of Faraday’s first law of electrolysis to calculate time for deposition;

(8) processes of converting ethanol to ethene, bromoethane and ethane;

(9) the use of electron box configuration to interpretate the rules in filling electrons into orbitals in an atom;

(10) building blocks of matter;

(11) factors that affect stability of radioactive nuclides and calculation of half life;

(12) what isotopes are and the differences between nuclear fission and nuclear fusion; (13) purification of bauxite to obtain aluminium; (14) definition of pH and calculations of [OH-] and [H+];

B. SUMMARY OF WEAKNESSES

The few weaknesses identified were:

(1) understanding the demand of the questions;

(2) lack of adequate knowledge of the chemical concepts, such as inductive effect and electrophiles;

(3) exhibition of poor communication skills in the delivery of answers;

(4) could not use bond dissociation energy to compare the acidity of HCl and HF;

(5) could not select organic compounds that could be cracked, undergo substitution reaction from among a list of compounds;

(6) could not explain why LiI(l) does not conduct electricity,

(7) use experimental data to explain rate of chemical reaction;

(8) calculation of enthalpy for a reaction from thermo-chemical data, define lattice energy and factors affecting it.

A. SUGGESTED REMEDIES

(1) Identification of the basic requirements of each question before answering;

(2) endeavour to use appropriate term of the subject when required;

(3) improvement of their communication skills;

(4) state correct and full definition of terms when required;

(5) learn how to explain concepts using the appropriate technical terms of the subject;

(6) start the study of organic chemistry on time;

(7) improve their study habits and behaviours.

WAEC Summary of 2021 WASSCE Chemistry Paper Two (2)

A. SUMMARY OF CANDIDATES’ STRENGTHS

The major strengths of the candidates identified as far as this paper was concerned include:

(1) periodic chemistry including chemical bonding and naming of complex ions;

(2) oxidation/reduction reactions, calculation of e.m.f. of cells from given half equations and the knowledge of the Faraday’s Laws;

(3) Stoichiometry and its application in determining percentage yield;

(4) calculations on solubility of salts and isotopic mass from the knowledge of relative atomic mass and percentage abundance;

(5) knowledge of radioactivity and its uses;

(6) dissociation of weak acids and bases in aqueous solution and the corresponding Ka and Kb expressions. Calculation of hydroxonium ion concentration;

(7) organic chemistry, isomerism, functional group identification and resonance in benzene.

A. SUMMARY OF WEAKNESSES

Despite the strengths mentioned and observed in several cases, some candidates were unable to present their answers in a systematic way. In such cases, the candidates were unable to score maximum marks. The major weaknesses identified in the candidates’ responses to the tasks involved in the questions include:

(1) the physical property that would enhance the separation of a mixture of water and palm-oil;

(2) comparison of the rates of forward and backward reactions for a reversible reaction at time zero;

(3) organic functional group identified with ammonical AgNO3(aq);

(4) how molecules assume their shapes and dipole moments in molecules;

(5) why the C=C bond energy is larger but not twice as that of C-C and why the bond energy of Cl2 is not the same as its bond dissociation energy

C. SUGGESTED REMEDIES

(1) Early completion of the syllabus.

(2) Candidates should have a thorough grasp of the principles behind the answers they provide.

(3) Routine administration of exercises on the various topics treated.

(4) Encouragement of extra learning with self examination.

WAEC Summary of 2021 WASSCE Chemistry Paper Three (3)

A. SUMMARY OF CANDIDATES’ STRENGTHS

The responses given by the candidates that need commendations are:

(1) they drew the titration tables, qualitative analysis tables very well and neat

(2) stated mole ratios correctly;

(3) there is an improvement in writing of values / figures of concentrations to 3 significant figures;

(4) correct units were also stated;

(5) colours and type of precipitates were stated;

(6) candidates followed instructions well and did the tests as demanded by the questions;

(7) correct inferences and observations were stated by most candidates except few who jammed things up;

(8) improvement in the use of concordant titre for averaging;

(9) performance for qualitative analysis in general was encouraging this year.

C. SUMMARY OF WEAKNESSES

(1) Candidates failed to acknowledge that a figure O after the decimal point does not count in writing significant figures but can only be included if it appears after a number e..g. 1, 2, 3 etc 0.037 is not 38 g figures but 0.0370.

(2) They also failed to state clearly when a precipitate is formed in drops of reagents and whether the precipitate dissolved in excess or not.

(3) They did not know the reactions of dilute acids on salts, that they either evolve gas, dissolve precipitate or have no reaction on the salts.

(4) They lack experience on practical activities which help them answer question 3 of the alternatives.

(5) Many of the candidates cancelled table of titre values and made new ones.

(6) Some candidates also tabulated their titre values in pencil before converting to ink.

(7) In some cases candidates performed tests that were not required.

(8) Regrettably many of the candidates wrote the formulae of reagents stated in the questions wrongly

C. SUGGESTED REMEDIES

(1) Teachers should do more hands on activities with their candidates, explain chemical terms and concepts to the students. They should not wait until examination instructions are sent before they start to perform practical with their students.

(2) Teachers should collect practical exercise books from the students, mark and discuss their strengths and weaknesses with them and advise them to work independently.

(3) Heads of schools must ensure that the schools have well equipped science laboratories with the materials for practical work. They must also endeavour to motivate the science teachers.

(4) Teachers on their part must make time to cover all the topics including practical activities in the syllabus.

(5) Students must also be encouraged to attend practical classes.

WAEC Summary of 2021 WASSCE Chemistry Paper Three (3)

A. SUMMARY OF CANDIDATES’ STRENGTHS

(1) Candidates could draw table of burette readings to 2 decimal places as required.

(2) Candidates understood the concept of mole ratio.

(3) Cations and anions were identified correctly by most of the candidates.

(4) Improvement in the use of concordant titres for averaging.

B. SUMMARY OF WEAKNESSES

(1) Significant figures still pose a challenge. Most of the candidates could not leave their answers to the right significant figures.

(2) Some candidates could not attach the correct units to the values calculated.

(3) Organic Qualitative Analysis question (Alt. A Question 2) was not well understood.

(4) Candidates could not attach correct states to the species in equations.

(5) Most candidates could not answer the question 3 in all the three alternatives.

(6) Difficulty in identification of colours of precipitates, residues and solution.

See also: WASSCE Candidates’ Strengths, Weaknesses In Integrated Science And Remedies | Extract From Chief Examiners Report For WASSCE 2023

C. SUGGESTED REMEDIES

(1) Teachers should find time to take the students through practical exercises and usual laboratory activities.

(2) Students should be encouraged to practice more questions on practical work.

(3) Students should be taken through the key points in:

– preparation of table of titre values;

– writing of test, observation and inference for qualitative analysis

It is the hope of our team that candidates will perform better when teachers and candidates go through this summary of strengths, WASECE candidates’ weaknesses in Chemistry and remedies and apply same.

Source: waecgh.org

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