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In this article, we’ll be looking into WAEC Chemistry questions and Answers for 2023. It include the 2023 WAEC Chemistry questions and Answers, Past questions and answers and all you need to know about the WAEC Chemistry Examination questions. Few hints is also included on how to pass WAEC Chemistry Examination.
NOTE: The 2023 WAEC Chemistry questions and answers have been posted here. SCROLL DOWN
Waec chemistry practical questions and answers 2023
CHEMISTRY -PRACTICAL INSTRUCTIONS
1. Great care should be taken to ensure that the information given in items 2 and 3 below does not reach the candidates either directly or indirectly before the examination.
2. In addition to the fittings and reagents normally found in a chemistry laboratory, the following apparatus and materials will be required by each candidate:
(a) One burette of 50cm3 capacity;
(b) One pipette, either 20cm3 or 25cm3. (All candidates at one centre must use pipettes 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 labeled;
(i) Dilute sodium hydroxide solution;
(ii) Dilute hydrochloric acid;
(iii) Dilute trioxonitrate (V) acid;
(iv) Silver trioxonitrate (V) solution;
(v) Acidified potassium dichromate solution;
(vi) Aqueous ammonia;
(vii) Lime water;
(viii) Red and Blue litmus paper;
(ix) Dilute tetraoxosulphate (VI) acid;
(x) Fehlings solution A & B.
(e) Spatula;
(f) Filtration apparatus;
(g) One beaker;
(h) One boiling tube;
(i) Four test tube;
(j) Methyl orange as indicator;
(k) Glass rod;
(l) Wash bottle containing distilled/deionized water;
(m) Burning splint;
(n) Watch glass;
(o) Bunsen burner/source of heat;
(p) Droppers;
(q) Mathematical table/calculator.
3. Each candidate should be supplied with the following, where ‘n’ is the candidate’s serial number.
(a) 150cm3 of a solution of HCL in a corked flask or bottle labeled ‘An’. These should all be the same containing 8.5cm3 of concentrated HCl per dm³ of solution.
(b) 150cm3 of Na2CO3 .10H2O in a corked flask or bottle labeled ‘Bn’. These should all be the same cointaing 5.0g of the hydrated salt per dm3 of solution.
(c) One spatulaful of glucose in a specimen bottle labeled ‘Cn’. This must be the same for all candidate
(d) One spatulaful of zinc oxide powder in a specimen bottle labeled ‘Dn’. This must be the same for all candidates.
4. In all cases, more materials may be issued if required.
5. The actual concentrations of A and B must be stated on the Supervisor’s Report Form. The candidates will assume that the concentrations are exactly as stated in the question paper.
6. It should be noted that schools are not allowed to amend the information provided on the question paper or substitute any substance/solution for those specified in these instructions.
ARRANGEMENT AND SERIAL NUMBERS OF CANDIDATES
7. The laboratory places should be numbered serially and the candidates should be allotted these places strictly in the order of their index numbers. The number of every specimen supplied to each candidate should be the same as his or her serial number.
8. If a candidate is absent, his or her serial number should not be allotted to another candidate.
9. If the candidates are divided into a number of sets, the serial numbers should be continued through the sets, so that no serial number is repeated.
Question 1 Answer
(1a)
Volume of pipette used, VA = 25.0cm³
Indicator Used = Methyl Orange
[TABULATE]
Burette Reading | Rough titre | 1st titre | 2nd titre |
Final Burette reading (cm³) | 25.60 | 32.80 | 26.40
Initial Burette reading (cm³) | 1.20 | 8.70 | 2.30
Volume of HCL used | 24.40 | 24.10 | 24.10
Average burette reading = (24.10 + 24.10)/2
volume of HCL used = 24.10cm³
*Number 3a*)
(i) If a few drops of NaOH solution are added to 2 cm^3 of a solution of Pb(NO3)2, a white precipitate of lead(II) hydroxide [Pb(OH)2] is formed. The balanced equation for the reaction is as follows:
Pb(NO3)2 + 2NaOH → Pb(OH)2 + 2NaNO3
(ii) If a few drops of NaOH solution are added to 2 cm^3 of a solution of Fe2(SO4)2, a green precipitate of iron(II) hydroxide [Fe(OH)2] is formed. However, on exposure to air, the Fe(OH)2 precipitate can be oxidized by atmospheric oxygen to form a reddish-brown precipitate of iron(III) hydroxide [Fe(OH)3]. The balanced equations for the reaction and the subsequent oxidation are as follows:
Fe2(SO4)2 + 4NaOH → 2Fe(OH)2↓ + Na2SO4
4Fe(OH)2 + O2 + 2H2O → 4Fe(OH)3
Therefore, the initial greenish precipitate of Fe(OH)2 will turn reddish-brown in color due to the oxidation to Fe(OH)3.
NUMBER 2
(2a)
TEST; C + distilled water + shake
OBSERVATIONS; It dissolves to give a colourless or clear solution
INFERENCE; Soluble salt suspected
(2ai)
TEST; Solution C + litmus paper
OBSERVATIONS; It has no effect on both blue and red litmus paper
INFERENCE; Neutral solution
(2aii)
TEST; solution C + Fehling solution A and B + heat
OBSERVATIONS; It gives a black red colour
INFERENCE; Reading agent confirmed
(2bi)
TEST; D + heat
OBSERVATIONS; It turns yellow on heating and white on cooling
INFERENCE; ZnO is present
(2bii)
TEST; D + dilute Hcl + heat
OBSERVATIONS; It dissolves completely to give a clear or colourless solution
INFERENCE; Solution chlorides of Zn³+, Al³+ is present
(2biii)
TEST; Solution D + NaOH in drops and then in excess
OBSERVATIONS; It gives white gelatinous precipitate. The precipitate is soluble in excess.
INFERENCE; Al³+, Zn²+ present.
Al³+, Zn²+ present .
(2biv)
TEST; Solution D + NH3 in drops and then in excess
OBSERVATIONS; It gives white gelatinous precipitate. The precipitate is soluble in excess NH3
INFERENCE; Al³+, Zn²+ is present.
Zn²+ confirmed.
•••••••••••••••••••••••••••••••••••••••••••••••••••
(3ai)
– Formation of a precipitate; Sodium hydroxide reacts with lead nitrate to form lead(ii) hydroxide as a precipitate.
Pb(NO3)2 + 2NaOH –> Pb(OH)2 + 2NaNO3
– Cloudiness or opacity; As the lead(ii) hydroxide precipitate forms, the solution may become cloudy or opaque due to the presence of the solid particles suspended in the liquid
(3aii)
– Formation of precipitate; Iron(iii) Fe(OH)3 is insoluble in water and appears as a reddish brown precipitate.
– Colour change; Colour change form yellowish to reddish brown
*NUMBER 3B*)
Obtain a small amount of benzoic acid and place it into a capillary tube.
Insert the capillary tube containing the benzoic acid sample into a melting point apparatus or a melting point apparatus.
Gradually heat the sample using the apparatus while observing the benzoic acid closely.
The temperature at which the solid benzoic acid completely melts and turns into a liquid is recorded as the melting point.
Repeat the process with multiple samples to ensure accuracy and reproducibility of results.
1. Great care should be taken to ensure that the
information given in items 2 and 3 below does not
reach the candidates either directly or indirectly
before the examination.
2. In addition to the fittings and reagents normally
found in a chemistry laboratory, the following
apparatus and materials will be required by each
candidate:
(a) One burette of 50cm3 capacity;
(b) One pipette, either 20cm3 or 25cm3.
(All candidates at one centre must use pipettes 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 labeled;
(i) Dilute sodium hydroxide solution;
(ii) Dilute hydrochloric acid;
(iii) Dilute trioxonitrate (V) acid;
(iv) Silver trioxonitrate (V) solution;
(v) Acidified potassium dichromate solution;
(vi) Aqueous ammonia;
(vii) Lime water;
(viii) Red and Blue litmus paper;
(ix) Dilute tetraoxosulphate (VI) acid;
(x) Fehlings solution A & B.
(e) Spatula;
(f) Filtration apparatus;
(g) One beaker;
(h) One boiling tube;
(i) Four test tube;
(j) Methyl orange as indicator;
(k) Glass rod;
(l) Wash bottle containing distilled/deionized water;
(m) Burning splint;
(n) Watch glass;
(o) Bunsen burner/source of heat;
(p) Droppers;
(q) Mathematical table/calculator.
3. Each candidate should be supplied with the
following, where ‘n’ is the candidate’s serial
number.
(a) 150cm3 of a solution of HCL in a corked flask
or bottle labeled ‘An’. These should all be the same
containing 8.5cm3 of concentrated HCl per dm³ of
solution.
(b) 150cm3 of Na2CO3 .10H2O in a corked flask
or bottle labeled ‘Bn’. These should all be the same
cointaing 5.0g of the hydrated salt per dm3 of
solution.
(c) One spatulaful of glucose in a specimen bottle
labeled ‘Cn’. This must be the same for all
candidate
(d) One spatulaful of zinc oxide powder in a
specimen bottle labeled ‘Dn’. This must be the
same for all candidates.
4. In all cases, more materials may be issued if
required.
5. The actual concentrations of A and B must be
stated on the Supervisor’s Report Form. The
candidates will assume that the concentrations are
exactly as stated in the question paper.
6. It should be noted that schools are not allowed
to amend the information provided on the question
paper or substitute any substance/solution for those
specified in these instructions.
More coming…
How to pass WAEC Chemistry Examination
Here are some common rules that you should apply when taking this exam.
- Start by answering questions you are sure of the Answers first.
- Do not spend more than a minute on each Objective questions. Remember you only have one hour
- Endeavor to recheck your work before submitting it.
- Make sure you attempt all the questions. Ensure to put something down; it is better than a blank page.
WAEC Chemistry Syllabus 2023
The resources below on Chemistry have been provided by WAEC to assist you to understand the required standards expected in Chemistry final Examination.
The examination in this subject is meant to test:
Note: Candidates are required to have knowledge of the significant figures, S.I. units, and the conventional/IUPAC system of nomenclature
AIMS: The aims and objectives of the syllabus are to assess candidates’
understanding of basic chemistry concepts;
level of acquisition of laboratory skills including awareness of hazards and safety measures;
level of awareness of the inter-relationship between chemistry and other disciplines;
level of awareness of the linkage between chemistry and industry/environment/everyday life in terms of benefits and hazards;
skills of critical and logical thinking.
Note: Candidates are required to have knowledge of the significant figures, S.I. units, and the conventional/IUPAC system of nomenclature.
You can see the complete WAEC Syllabus via this link CHEMISTRY-converted
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