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WAEC GCE Chemistry Questions and Answers 2023/2024 (Essay and Objectives)
WAEC GCE Chemistry Questions and Answers 2023 . Welcome to 2023 WAEC Chemistry Questions and Answers. You will find WAEC GCE Chemistry Objective Answers, WAEC Chemistry Essay 2023, WAEC GCE 2023 Chemistry, and the tips you need to pass your WAEC GCE Chemistry examination with ease.
Table of Contents
WAEC GCE Chemistry Questions and Answers 2023 (Expo)
The 2023 WAEC GCE Chemistry expo will be posted here during the WAEC GCE Chemistry examination. Keep checking and reloading this page for the answers.
WAEC GCE 2023 Chemistry Answers Loading.. .
Today’s WAEC GCE Chemistry OBJ Answers:
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Note: The answers below are the 2020 Nov/Dec answers.
NOTE: Pls Trace It From Your Objective. [If you see any options here pick it from your objectives]
1 Involves the loss and gain of electrons 2 Polymerisation 3 Global warming 4 3 5 Zinc ions 6 +1.56V 7 Ethene 8 NH3 9 Propanol 10 28 11 Hydrolysis 12 d-orbital 13 Lowering the activation energy 14 Closeness between reactant particles 15 Remaining the same with time 16 Reaction vessel Fels cool during the reaction 17 Faster 18 Solvent extraction 19 Saturated Solution 20 2.75mol/dm³ 21 Partially dissociates in aqueous solution 22 138g 23 HI 24 2.00cm³ 25 hydrogen chloride 26 strong electrovalent bond between ions 27 is not ductile 28 Electrons 29 C2H4 30 Aluminium 31 0.010mol/dm³ 32 PbCO3 33 Linear 34 HCL and HOCL 35 +1 36 Ionic bond 37 have relatively low ionization energy 38 sour to taste 39 I,III and IV only 40 chrometography 41 2.00 dm 42 mole of solvent in 1dm³ of solution 43 does not contain neutron 44 1s²2s²2p⁶ 45 Ammonium chloride 46 IV 47 I,II and IV only 48 Quantum numbers of Electrons 49 -273⁰C 50 Mass number
1-10: DDDADBBABA
11-20: CDABDCCDDC
21-30: ACDBDCCDAB
31-40: BCADABDBAC
More Answers loading…
WAEC GCE Chemistry Theory Answers:
(i) Sodium trioxonitrate (v) decahydrate
NaNO₃ . 10H₂O
(ii) Sodium Oxide –> Na₂O
(iii) Potassium tetraoxophospate (v) –> K₃PO₄
Products formed are:
Hydrogen gas (a+ cathode)
Chlorine gas (a+ anode)
it decrease down the group
As the atomic radius increases down the group the attraction of the positive nucleus of the electron outer most electron, thus the ionization energy decreases
Nitrogen and carbon (ii) oxide
it is used to heat furnace
it is a source of nitrogen for the manufacture of ammonia
Sodium hydrogen – used in qualitative analysis
– Purification of bauxite
Sodium trioxocarbonate (iv)
-Manufacture of glass
-As a water soften
2-amino propane
(2ai) Percentage C5H12 of mass m = 7.2g Volume of O2 = 20.0dm³ (i) from the general combustion equation CxHy(g) + (x+y/4)O2 –> XCO2 + y/2H2O C5H12(l) + 802(g) –> 5CO2(g) + 6H2O(l)
(2aii) 1 mole of C5H12(72g) = 5 moles of CO2 At stop 7.2gC5H12 = x volume of CO2 X = 7.2g×5×22.4dm³/72g X = 5×2.224 = 11.2dm³ of CO2
(2aiii) Volume of oxygen left after the reaction from the equation of reaction 1 mole of C5H12(72g) = 8(22.4)dm³ 7.2g = x X = 7.2×8×22.4/72 = 17.92dm³ Volume of O2 left after the reaction = 20.0dm³ – 17.92dm³ = 2.08dm³
(2b) When molecules collide with one another they possess kinetic energy. As most energetic molecules (those with greater kinetic energy) try to escape. Their escape may be facilitated by heat or by passing a wave of air over the container or by increasing the surface area of the container. As they try to do this, some molecules will loose energy on collision and fall back to the container; as such the average kinetic of the molecules of the liquid in the container reduces which results to cooling effect.
(2ci) Avogadro’s Law states that the total number of atoms/molecules of a gas (i.e. the amount of gaseous substance) is directly proportional to the volume occupied by the gas at constant temperature and pressure.
(2cii) N2(g) + 3H2—> 2NH3 Where 1 mole = 30cm³ of gas
At constant temperature, the volume of a fixed mass of gas. When the volume of a cylinder or a container is increased, the gases have more space to travel and collide hence the pressure is reduced but as the volume is decreased or compressed the gases have less space to travel therefore more pressure is built up.
No (3ai) ¹³R, ⁸Q ¹³R=1s²,2s²,2p⁶,3s²,3p¹ ⁸Q=1s²,2s²,2p⁴
(3aii) ¹³R=2,8,3 Valency of ¹³R is 3 ⁸Q= 2,6 Valency of ⁸Q=2
(3di) 2H² SO4(aq)+4NaOH(aq)—>2Na² SO4(aq)+4H²O(s)
(3dii) Sodium teraoxosulphate (iv) salt and water
(3diii) The resulting solution NaSO4 is basic and will have no effect on litmus paper
(3div) When heated to dryness it can be used as a dehydrating agent
Typing….
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The questions below are strictly for practice.
1. Which of the following statements best explains the difference between a gas and a vapour?
(a) Unlike gases, vapours are liquids at room temperature
(b) Unlike gases, vapour can easily be condensed into liquids
(c) Unlike gases, vapour is readily converted into solids
(d) Vapours are generally denser than gases
2. Consider the following reaction equation: 2HCI + Ca(OH) 2 → CaCI 2 + H 2 O. what is the volume of 0.1 moldm -3 , HCI that would completely neutralize 25 cm 3 or 0.3 moldm -3 Ca(OH) 2 ?
(a) 150 cm 3
(b) 75 cm 3
(c) 30 cm 3
(d) 25 cm 3
3. Cu and HNO 3 are not suitable for preparing hydrogen gas because of their
(a) Reactivity and oxidation respectively
(b) conductivity and corrosiveness respectively
(c) melting point and reduction respectively
(d) electronegativity and solubility respectively
4. Which of the following formulae cannot be an empirical formula?
(c) P 2 O 5
(d) N 2 O 4
5. One of the criteria for confirming the purity of benzene is to determine its
(a) Heat capacity
(b) boiling point
6. When chlorine is passed through a sample of water, the pH of the water sample would be (a) <7
(a) 1.20 x 10 23
(b) 2.41 x 10 23
(c) 3.62 x 10 23
(d) 4.82 x 10 23
8. The strength of metallic bonds depends on the
(a) charge density of the atoms
(b) ductility of the metal
(c) number of valence electrons
(d) total number of electrons in the atoms
9. When zinc is added to AgNO 3 solution, crystals of silver forms on the zinc surface. This indicates that zinc is
(a) oxidized
(b) reduced
(c) decomposed
(d) dissociated
(d) Cu 2 O 2
- WAEC GCE Mathematics Questions and Answers
- WAEC GCE Physics Questions and Answers
11. The change in the oxidation state of iron in the reaction represented by the equation below is 2FeCI 3 + H 2 S →2FeCI 2 + 2HCI + S
(a) +2 to +3
(b) +3 to +2
(c) 0 to +2
(d) +3 to 0
12. Which of the following methods can be used to separate blood cells from plasma?
(a) Centrifugation
(b) Filtration
(c) Chromatography
(d) Distillation
13. Which of the following statements about ionic radius is correct? ‘Ionic radius
(a) Increases as nuclear charge increases
(b) decreases as nuclear charge increases
(c) decreases as nuclear charges decreases.
(d) remains constant as nuclear charge increases
14. Analysis of a hydrocarbon shows that it contains 0.93 g of carbon per gram of the compound. The mole ratio of carbon to hydrogen in the compound is [H=1.0, C=12.0]
15. The law of definite proportions states that
(a) pure samples of same compound contain the same elements combined in the same proportion by mass
(b) pure samples of substances are in the same proportion by mass
(c) chemical compounds are pure because they contain the same elements
(d) matter can neither be created nor destroyed
17. Atoms are electrically neutral because they
(a) don not conduct electricity
(b) contain equal number of protons and electrons
(c) are composed of neutrons and electrons
(d) cannot be attracted by electromagnetic field
18. Common salt (NaC1) is used for preserving foods. Which of the following properties could be used to determine its purity before use?
(a) Solubility in water
(b) melting point
(c) Relative density
(d) Crystalline nature
19. Which of the following electron configurations represents the transition element chromium ( 24 Cr)?
(a) 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 4
(b) 1s 2 2 2s 2 2p 6 3s 2 3p 6 3d 6
(c) 1s 2 2s 2 2p 6 2s 2 3d 4 4s 1 (d) 1s 2 2s 2 2p 6 3s 2 3p 6 4s 1 3d 5
20. The atomic number of an isotope of hydrogen is equal to its mass number because it
(a) has a totally filled valence shell
(b) has a high charge to mass ratio
(c) does not contain neutrons (d) exhibits isotopy
21. The total number of shared pair of electrons in the compound below is
22. The bonding pair of electrons in a hydrogen chloride molecule is pulled towards the chlorine atom because
(a) Chlorine has a larger atomic size
(b) chlorine has a large atomic mass
(c) chlorine is more electronegative
(d) there is no bonding orbitals within the hydrogen atom
23. The solubility of CO 2 in water can be accounted for by
(a) van der waal’s forces
(b) ionic attraction
(c) dipole attraction
(d) covalent bonding
24. Which of the following properties would not influence electrovalent bond information?
(a) Electronegativity
(b) Electron affinity
(c) Ionization potential
(d) Catalytic ability
25. Particles in a solid exhibit
(a) Vibrational motion only
(b) vibrational and translational motion
(c) vibrational and random motion
(d) random and translational motion
WAEC GCE Chemistry Essay 2023
The above questions are not exactly 2023 WAEC Chemistry questions and answers but likely WAEC Physics repeated questions and answers.
These questions are for practice. The 2023 WAEC GCE Chemistry expo will be posted on this page 30 minutes before the WAEC GCE Chemistry examination starts. Keep checking and refreshing this page for the answers.
If you have any questions about the WAEC GCE Chemistry questions and answers, kindly drop your questions in the comment box.
Last Updated on October 2, 2023 by Admin
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Chemistry Paper 2 (Practical), WASSCE (SC), 2023
- Subject Home
(a) What is transition element? [2 marks]
(b) Consider the electron configuration of the following elements: A= 2: 8:6; B = 2: 8:2; C = 2:8:1; D = 2:8:8 State the element which forms a: (i) doubly charged cation; (ii) soluble trioxocarbonate (IV). [2 marks]
(c) Explain briefly why there is a general increase in the first ionization energies of the elements across the period in the periodic table. [2 marks]
(d) Give two examples of an aliphatic compound. [2 marks]
(e) Explain briefly why alkanols are stronger bases than water [3 marks]
(f) State the major raw materials used in the solvay process. [3 marks]
(g) What is geometric isomerism? [2 marks]
(h) Give a reason why water gas is a better fuel than producer gas.
(i) Define the term heat o/’combustion.
(j) (i) State Faraday second law of electrolysis.
(ii) Calculate the amount of silver deposited when 10920 coulombs of electricity is passed through a solution of a silver salt. [IF = 96500 c mol-1] [5 marks]
Observation
In part (a), majority of the candidates could not define a transition element.
In part (b), majority of the candidates stated the element which forms a doubly charged cation and soluble trioxocarbonate (IV).
In part (c), majority of the candidates explained why there is a general increase in the irst ionization energies o the elements across the period in the periodic table.
In part (d), majority of the candidates gave two examples of an aliphatic compound. In part (e), majority of the candidates could not explain why alkanols are stronger bases than water.
In part (f), majority of the candidates stated the major raw materials used in the solvay process.
In part (g), majority of the candidates could not define geometric isomerism.
In part (h), majority of the candidates gave a reason why water gas is a better fuel than producer gas.
In part (i), majority of the candidates stated Faraday’s second law of electrolysis . However, few candidates were able to calculate the amount of silver deposited when 10920 coulombs of electricity is passed through a solution of a silver salt if 1F =96500 C mol-1 ).
The expected answers include:
(a) A transition element is one which has incompletely filled d-orbitals.
(b) (i) B (ii) C
(c) Across a period (from left to right) there is a gradual increase in the number of protons in the nucleus / effective nuclear-charge . This increases the force of attraction between the nucleus and the electrons, hence more energy is needed to remove the outermost electron.
(d) - methane - ethene - ethyne - ethanol - ethanoic acid
(e) - Alkanols are formed by replacing one hydrogen of water by an alkyl group (1) - Alkyl groups have a positive inductive effect / are electron releasing/ electron donating - This increases the electron density of the oxygen
(f) - NaCl - CaCO3 - NH3 - C
(g) Geometric isomerism is the existence of two compounds with the same molecular formula but differ in the arrangement of groups attached to the carbon containing the double bond
(h) This is because constituents of water gases (CO and H2) are both combustible and give a higher calorific / heat value than producer gas.
(i) It is defined as the heat change/ released when 1 mole of a substance is burnt in excess oxygen OR It is defined as the heat change/ released when 1 mole of a substance is completely burnt in air
(j) (i) When the same quantity of electricity is passed through different electrolytes, the relative number of moles of the elements discharged are inversely proportional to the charges on the ions of the element.
(ii) 96500 C liberates 1.0 mol of Ag(s) ∴ 10920 C will liberate 10920 96500 = 0.113 mole