WAEC Chemistry Questions and Answers for 2023/2024 (Theory and Objectives)

2023 WAEC Chemistry Answers, WAEC Chemistry questions and answers, WAEC Chemistry questions and everything you need to know about 2023 WAEC Chemistry Examination will be provided in this article. You will find Chemistry Paper 1 (Objective) and Chemistry 2 (Essay) here

Scroll to the bottom for today’s Chemistry Answers

Below are the WAEC Chemistry questions. Read them and get ready to score high in your WAEC Chemistry exam.

The West Africa Examination Council (WAEC) is an examination body in Nigeria that conducts the Senior Secondary Certificate Examination and the General Certificate in Education in May/June and November/December respectively.

WAEC Chemistry Questions and Answers 2023

WAEC Chemistry Questions and Answers 2023 Loading…

The 2023 answers will be posted here on 24th May during the exam

WAEC Chemistry OBJ Answers Loading…

1-10: ACADABBDAC

11-20: BCAABBCCBB

21-30: ACBABDACBB

31-40: ABBDAADCDD

41-50: BDCDDCDDCD

(1a)

A transition element, also known as a transition metal, is an element that belongs to the d-block of the periodic table.

(1b)

(i) Element B (2:8:2)

(ii) Element C (2:8:1)

(1c)

The increase in the first ionization energies across a period is mainly due to the increasing effective nuclear charge and decreasing atomic radius. The stronger pull from the increasing nuclear charge and the closer proximity of the electrons to the nucleus make it harder to remove an electron, leading to higher ionization energies.

Number 1di)

Two examples of aliphatic compounds are:

A. Ethane (C2H6): Ethane is a saturated hydrocarbon belonging to the alkane family. It consists of a straight chain of two carbon atoms bonded to each other, with six hydrogen atoms attached to the carbons.

B. Butanol (C4H10O): Butanol is an alcohol with a four-carbon straight chain. It has the chemical formula C4H10O and exists in four isomeric forms: n-butanol (normal butanol), sec-butanol (secondary butanol), isobutanol (isopropyl alcohol), and tert-butanol (tert-butyl alcohol).

No 3

No (5)

*ai)*…

*Reaction between Iron (Fe) and Dilute H2SO4:*

Iron reacts with dilute sulfuric acid to form iron sulfate (FeSO4) and hydrogen gas (H2). The balanced chemical equation for this reaction is:

3Fe(s) + 4H2SO4(aq) -> 3FeSO4(aq) + 2H2(g) + 2H2O(l)

In this reaction, iron displaces hydrogen from the acid, resulting in the production of iron sulfate and hydrogen gas. The iron sulfate is soluble in water and remains in solution, while the hydrogen gas is released as a gas.

*Reaction between Aluminum (Al) and Dilute H2SO4:*

Aluminum reacts differently with dilute sulfuric acid due to the protective oxide layer that forms on its surface. The oxide layer prevents further reaction by acting as a barrier between the aluminum metal and the acid. However, the reaction can occur if the protective layer is disrupted or removed

2Al(s) + 3H2SO4(aq) -> Al2(SO4)3(aq) + 3H2(g)

In this reaction, aluminum sulfate (Al2(SO4)3) and hydrogen gas are produced. The aluminum sulfate formed is soluble in water and remains in solution, while the hydrogen gas is liberated as a gas.

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The questions below are the WAEC Chemistry Questions. Go through them and be ready to score high in your WAEC 2023 Chemistry Examination.

1. What condition favours the formation of the product for the endothermic reaction, N2O4(g) —><—– 2NO2(g)

A. Decrease in pressure

B. A decrease in volume

C. An increase in pressure

D. A constant volume

ANSWER: A ( Decrease in pressure)

2. How many alkoxy alkanes can be obtained from the molecular formula C₄ H₄O₄

A. 1

B. 2

C. 3

D. 4

ANSWER: C (3)

3. Element Y has two isotopes Y and Y present in the ratio 1:3. The relative atomic mass of Y would be

A. 20.5

B. 21

C. 21.5

D. 22

ANSWER: C (21.5)

4. 100.0g of KClO₃ was added to 40.0 cm^3 of water to give a saturated solution at 298K. If the solubility of the salt is 20.0 moldm^-3 at 298K, what percentage of the salt is left undissolved? {K= 39, Cl = 35.5, O = 16}

A. 80%

B. 60%

C. 5%

D. 2%

5. Elements X and Y have electronic configuration 1S²2S²2P⁴ and 1S²2S²2P⁶3S²3P¹ respectively. When they combine the formula of the compound formed is

A. XY

B. Y₂X₃

C. Y₂ X₃

D. Y X₂

ANSWER: B (Y₂X₃)

Recommended: WAEC Timetable

6. A solution of 0.20 mole of NaBr and 0.20 mole of MgBr₂ in 2.0 dm³ of water is to be analysed. How many moles of Pb(NO₃ )₂ must be added to precipitate all the bromide as insoluble PbBr₂

A. 0.30 mol

B. 0.10 mol

C. 0.20 mol

D. 0.40 mol

ANSWER: A (0.30 mol)

7. Na₂CO₃ + HCl —-> NaHCO₃ + NaCl. The indicator most suitable for this reaction should have pH equal to.

A. 3

B. 5

C. 7

D. 9

ANSWER: D (9)

8. A satuarted solution of silver trioxocarbonate (IV), was found to have concentration of 1.30 x 10^-5 moldm^-3 . The solubility product of the trioxocarbonate (IV) is

A. 8.79 x 10^-15

B. 1.69 x 10^-10

C. 1.82 x 10^-11

D. 9.84 x 10^-10

ANSWER: A (8.79 x 10^-15)

9. When platinum electodes are used during the electrolysis of copper (II) tetraoxosulphate (IV) solution, the solution gets progressive

A. Acidic

B. Basic

C. Neutral

D. Atmospheric

ANSWER: A (Acidic)

10. Tetraoxosulphate (VI) ions are final test using

A. acidified silver nitrate

B. acidic barium chloride

C. lime water

D. dilute hydrochloric acid

ANSWER: D (dilute hydrochloric acid)

See:

• WAEC Physics Questions and Answers
• WAEC Biology Questions and Answers
• WAEC English Questions and Answers

WAEC 2020 Chemistry Theory Questions

PAPER 2 (ESSAY)

SECTION A

1. Identify the solid remaining when each of the following is heated.
(a) lithium trioxonitrate (V)
(b) potassium trioxonitrate (V)
(c) calcium trioxonitrate (V)

2. (a) When calcium oxide and coke are heated in an electric furnace, the products are carbon (ii) oxide and calcium carbide (CaC2), write the equation for this reaction.

(b) The addition of water to calcium carbide leads to the formation of calcium hydroxide and ethyne. Write the equation for the production of ethyne.

3. Calculate the percentage by mass of silicon tetrachloride. [2 marks]
4. Ammonia, NH3, and phosphine, Ph3, are the hydrides of the first two elements in group 5.
(a) Draw a dot and cross diagram for the ammonia molecule. [2 marks]
(b) Sketch and explain the shape of the ammonia molecule. [3 marks]

5. The first ionization energy of chlorine is +1260KJmol-1.
(a) Define the term first ionization energy.
(b) State and explain the general trend in the values of the first ionization energy for the elements across the period, sodium to argon in the periodic table.

6. Compound A consisting of carbon and hydrogen only. The compound was found to contain 80% carbon by mass.
(a) Calculate the empirical formula of compound A using the data above.
(b) The relative molecular mass of compound A was found to be 30.
Use this information to deduce the molecular formula of compound A.
[H = 1.00 C = 12.00]

7. State two factors other than a change in temperature or the use of a catalyst that influence the rate of a chemical reaction.

SECTION B

1. (a) Two elements represented by the letters Q and R have atomic numbers 9 and 12 respectively.
(i) Write the election configuration of R.
(ii) To what group does Q belong in the periodic table.
(iii) Write the formula of the compound formed when Q combines with R.
(iv) Explain briefly, why Q is a good oxidizing agent.
(v) State whether R would be expected to form acidic or basic oxide.
(b) (i) State two assumptions of the kinetic theory of gases.
(ii) When some solids are heated, they change directly into the gaseous state. What name is given to this phenomenon?
(iii) List two substances which exhibit the phenomenon mentioned in (ii).
(iv) Write an expression to show the mathematical relationship between the rate of diffusion of a gas and its vapour.

2. An aqueous solution has a pH of 4.0.
(a) (i) What is the hydrogen ion concentration of the solution?
(ii) What effect will it have on litmus paper?
(iii) Which of the following salt solutions would have the same effect on litmus? Give a reason for your answer. NH4Cl(aq); NaCl(aq) ; CH3OON(aq).
(b) (i) Differentiate between a fine chemical and a heavy chemical.
(ii) Name two sources of air pollution.
(iii) Suggest one way of reducing air pollution in cities

3. (a) (i) Explain briefly the fermentation process.
(ii) Write a balanced equation for the fermentation of glucose.
(iii) What substance must be added to glucose solution to ferment it?
(iv) Explain briefly why tightly corked glass filled to the brim with palm wine shatters on standing.
(b) State one industrial application of each of the following methods of separation:
(i) Crystallization;
(ii) Fractional distillation.
(c) Explain the following terms:
(i) Saponification;
(ii) Esterification.
(d) Write a balanced equation to illustrate each of the terms in (c).
(e) i) What is hydrocarbon compound?
(ii) Name two principal sources of hydrocarbons.

WAEC Chemistry Essay and Objective 2023 (EXPO)

The above questions are not exactly 2023 WAEC Chemistry questions and answers but likely WAEC Chemistry repeated questions and answers.

These questions are for practice. The 2023 WAEC Chemistry expo will be posted on this page during the WAEC Chemistry examination. Keep checking and refreshing this page for the answers.

Keep reloading this page for more answers

Tips to Pass WAEC Chemistry Questions

1. Study Hard

It is known to everyone that hard work brings success. Ensure to read the chemistry textbooks recommended by The West Africa Examination Council (WAEC).

This will help you to take a look at most of the questions you will see on the day of WAEC Chemistry examination.

Let me clearly state that questions are not imported from heaven but from those textbooks recommended by WAEC.

2. Read WAEC Chemistry Past Questions

WAEC usually picks questions from the previous years to form fresh questions. Studying WAEC Chemistry past questions would give you an idea of how WAEC Chemistry questions are set.

3. Start Preparing for WAEC 2023 :

Stop wasting your time. Now that you have gotten textbooks and past questions, the next thing is to begin your reading. Early reading and practice is good for you; you will pass well on WAEC 2023 Chemistry

4. Solve and try to understand every example and exercise you see in textbooks

It is very unfortunate that Secondary school students are fond of skipping exercises and even examples while studying textbooks.

They loved notebooks so much that they could ask, “can I read my Chemistry notebook and pass WAEC 2023?”. Don’t be scared of attempting exercises; they are there to help you. Face it and overcome it!

5. Practise Regularly

Don’t get discouraged when certain topics are annoying, keep on practicing until you master everything. Never give up and never say never. Keep pushing….

If you have any questions about WAEC Chemistry Questions and Answers for 2023, kindly drop your question in the comment box and please, remember to share this information by clicking the Facebook share icon or any of the social media share icons below.

Last Updated on May 24, 2023 by Admin