NECO Chemistry Questions and Answers 2023. I will be showing you past Chemistry objectives and theory repeated questions for free in this post. You will also understand how NECO Chemistry questions are set and how to answer them.
The National Examinations Council (NECO) is an examination body in Nigeria that conducts the Senior Secondary Certificate Examination and the General Certificate in Education in June/July and December/January respectively.
NECO Chemistry Objectives and Essay Answers 2023 (Expo)
The 2023 NECO Chemistry expo will be posted here during the NECO Chemistry examination. Keep checking and reloading this page for the answers.
NECO 2023 Chemistry Answers Loading.
Note: The answers are for the 2022 NECO exam.
(i) KAl(SO₄)₂. 12H₂O
Number of moles of sodium reacted = reacting mass/molar mass
Number of moles of oxygen reacted = (1/4) x Number of sodium
= 1/4 x (3.6/23)
Reacting mass of oxygen = Number of moles x molar mass
= 0.03913 x (16×2)
Air in gaseous form is first passed through caustic soda to remove CO₂. It is compressed and cooled until ut becomes a liquid at -200°C. It is then led to a fractionating column. On distillation, Nitrogen which has a lowet boiling point of -196°C is evolced first leaving behind Oxygen in liquid form. Further heating converts the liquid to a gas at -183°C.
(i) It is used for combustion
(ii) It is used for artificial respiration
This is because room temperature is warmer
(i) Methyl orange
An ion is an atom or molecule which has a net electric charge due to the loss or gain of one or more electrons.
HCl gas doesn’t contain ions
(i) Noble gases: Neon, Helium
(ii) Halogens: Iodine, Fluorine
(iii) Alkaline earth metals: Calcium, Magnesium
Halogens attain stable octet configuration by accepting an electron from donors Group I elements.
A sol is a colloid where solid particles are dispersed in liquid medium.
(i) Acid-base titrations are used to determine the percentage purity of a substance
(ii) Acid-base titrations are important to determine the number of water molecules in a hydrate.
A molar solution of a compound contains one mole or the molar mass of the compound in one dm³ of the solution.
(i) Identification of gases
(ii) Identification of acidic and metallic radicals
(i) Purification of bauxite
(ii) Electrolysis of alumina
This is because of the presence of copper which is a transition metal
(i) Methanamide is a liquid while the rest amides are crystalline solids
(ii) Melting points and boiling points of aides are much higher than expected.
(i) Heavy chemicals are produced in very large quantities in industries While fine chemicals are produced in small quantities for specific purposes
(ii) Heavy chemicals are in a crude state while fine chemicals are purified.
(i) Million’s reagent
(ii) Feeling’s solution
Graham’s law of diffusion states that at a constant temperature and pressure the rate of diffusion of a gas is inversely proportional to the square root of its density.
RO₂/RCH₄ = √(MCH₄/MO₂)
5/(200/t) = √[(12+4)/(16×2)]
5t/200 = √16/32
t/40 = 1/√2
t = 40/√2
t = (40/√2) × (√2/√2)
t = 20√2 seconds
Time taken = 28.28 seconds
I – C₂H₂OH + H₂SO₄ —>C₂H₅HSO₄ + H₂O
II – C₂H₅HSO₄ —> C₂H₄ +H₂SO₄
(i) They incompletely filled d-orbitals
(ii) They exhibit variable oxidation state
(i) It is used in making aeroplane parts due to its tensile strength
(ii) It is used in making window frames because it cannot be easily oxidised
A white precipitate is formed with evolution of brown gas
(i) Hydrogen bond
(ii) Covalent bond
H₂SO₄ + 2NaOH —> Na₂SO₄ +2H₂O
CaVa/CbVb = Na/NB
Va = CbVbna/Can
Va = 0.1×25×1/0.5×2
Va = 2.5cm³
Rate of a chemical reaction is defined as the number of moles of reactant converted or product formed per unit time.
Mass of CaCO3 = 3g
Molar mass of CaCO3= 100g/mol
No. of moles = 3/100 = 0.03
Time = 2×60 = 120s
Rate of reaction = No. of moles/Time
= 0.03/120 = 2.5 × 10-⁴
(i) They are more resistant to corrosion
(ii) They are more durable
(iii) They have lower melting point
2Pb(NO₃)₂ —> 2PbO + 4NO₂ +O₂
I =Hard water=
(i)It has better taste than soft water
(ii) It can be supplied in lead pipes as it does not dissolve lead
II =Soft water=
(i) It does not deposit scale in boilers and fur in kettles
(ii) It does not waste soap
I – CO
II – SO₂
I – Hardness
II – Lustre appearance
III – Conductivity
IV – Ability to absorb
4.3/2.12 = 142+18x/142
2.12(142+18x)/2.12 = 4.3*142/2.12
142+18x = 288
18x = 288-142
x = 146/18
x = 8
The following NECO Chemistry questions are questions to expect in the 2022 NECO examination.
1. The minimum amount of energy required for effective collisions between reacting particles is known
A) Activation energy
B) Bond energy
C) Kinetic energy
D) Potential energy
2. The bond formed between H2OH2O and H+H+ to form the hydroxonium H3O+H3O+ is
3. An element XX forms the following oxides X2O,XOX2O,XO and XO2.XO2. This phenomenon illustrates the law of ________.
A) Conservation of mass
B) Definite proportion
C) Mass action
D) Multiple proportion
4.. How many moles of oxygen would contain 1.204×10241.204×1024 molecules?
NB: Avogadro’s constant (NA) =6.02×1023=6.02×1023
See: NECO Timetable
5. Which of the following statements about solids is correct?
A) Solid particles are less orderly than those of a liquid
B) Solid have lower densities than liquids
C) Solid particles have greater kinetic energies than those of liquids
D) Solid particles cannot be easily compressed
6. Which of the following apparatus can be used to measure a specific volume of a liquid accurately?
B) Conical flask
C) Measuring cyclinder
7. The general gas equation PVT=KPVT=K is a combination of
A) Boyle’s and Charles’ laws
B) Boyle’s and Graham’s laws
C) Charles’ and Graham’s laws
D) Dalton’s and Graham’s laws
8. The spreading of the scent of a flower in a garden is an example of?
A) Brownian motion
D) Tynadal effect
9. Propane and carbon (IV) oxide diffuse at the same rate because [H = 1.00, C = 12.0, O = 16.0]
A) They are both gases
B) Their molecules contain carbon
C) They have the same relative molecular mass
D) Both are denser than air
1O. The energy which accompanies the addition of an electron to an isolated gaseous atom is
C) Electron affinity
11. A sample of hard water contains some calcium sulphate and calcium hydrogen carbonate. The total hardness may therefore be removed by
A. boiling the water
B. adding excess calcium hydroxide
C. adding a calculated amount of calcium hydroxide
D. adding sodium carbonate
E. adding magnesium hydroxide
12. During the electrolysis of copper II sulphate between platinum electrodes, if litmus solution is added to the anode compartment,
A. the litmus turns blue but no gas is evolved
B. the litmus turns blue and oxygen is evolved
C. the litmus turns blue and hydrogen is evolved
D. the litmus turns red and oxygen is evolved
E. the litmus turns red and then becomes colourless
13. The reaction between an organic acid and an alcohol in the presence of an acid catalyst is known as;
14. The IUPAC names of the compounds CH3COOH and CH2=CH2 are respectively;
A. acetic acid and ethane
B. ethanoic acid and ethene
C. methanoic acid and ethylene
D. ethanol and ethene
E. acetic acid and ethylene
15. If 30cm3 of oxygen diffuses through a porous pot in 7 seconds, how long will it take 60cm3 of chlorine to diffuse through the same pot, if the vapour densities of oxygen and chlorine are 16 and 36 respectively?
A. 9.3 sec
B. 14 sec
C. 21 sec
D. 28 sec
E. 30.3 sec
16. When heat is absorbed during a chemical reaction, the reaction is said to be
17. When large hydrocarbon molecules are heated at high temperature in the presence of a catalyst to give smaller molecules, the process is known as
18. The pH of four solutions W, X, Y, Z are 4, 6, 8, 10 respectively, therefore
A. none of these solutions is acidic
B. the pH of Y is made more acidic by addition of distilled water
C. Z is the most acidic solution
D. W is the most acidic solution
E. X is neutral
19. When each of the nitrates of Potassium, Magnesium and iron is heated,
A. all the nitrates decompose to their oxides
B. the nitrate of magnesium gives the nitrite and oxygen
C. the nitrates of iron magnesium and iron give the oxides
D. the nitrate of iron gives the nitrite and oxygen
E. the nitrate of the magnesium is not decomposed
2O. Which of the following metals cannot replace hydrogen from water or steam?
21. small quantity of solid ammonium chloride (NH4Cl) was heated gently in a test tube, the solid gradually disappears to produce two gases. Later, a white cloudy deposit was observed on the cooler part of the test tube. The ammonium chloride is said to have undergone
22. Elements P, Q, R, S have 6, 11, 15, 17 electrons respectively, therefore,
A. P will form an electrovalent bond with R
B. Q will form a covalent bond with S
C. R will form an electrovalent bond with S
D. Q will form an electrovalent bond with S
E. Q will form a covalent bond with R
23. An element X forms the following compounds with chlorine; XCl4, XCl3, XCl2. This illustrates the
A. law of multiple proportions
B. law of chemical proportions
C. law of simple proportions
D. law of conservation of mass
E. law of definite proportions
24. The oxidation state of chlorine in potassium chlorate is
25. 10 When air which contains the gases Oxygen, nitrogen, carbondioxide, water vapour and the rare gases, is passed through alkaline pyrogallol and then over quicklime, the only gases left are;
A. nitrogen and carbondioxide
B. the rare gases
C. nitrogen and oxygen
D. nitrogen and the rare gases
E. nitrogen, carbondioxide and the rare
26. Which of the following statements is NOT correct?
A. The average kinetic energy of a gas is directly proportional to its temperature
B. At constant tempearture, the volume of a gas increases as the pressure increases
C. The pressure of a gas is inversely proportional to its volume
D. The temperature of a gas is directly proportional to its volume
E. The collisions of molecules with each other are inelastic
27. Zinc Oxide is a
A. Basic Oxide
B. Acidic Oxide
C. Amphoteric Oxide
D. Neutral Oxide
E. Reactive Oxide
28. When sodium chloride and metallic sodium are each dissolved in water
A. both processes are exothermic
B. both processes are endothermic
C. the dissolution of metallic sodium is endothermic
D. the dissolution of metallic sodium is exothermic
E. the dissolution of sodium chloride is explosive
29. The periodic classification of elements is an arrangement of the elements in order of their
A. Atomic Weights
B. Isotopic Weights
C. Molecular Weights
D. Atomic Numbers
E. Atomic Masses
3O. In the reaction between sodium hydroxide and sulphuric acid solutions, what volume of 0.5 molar sodium hydroxide would exactly neutralise 10cm3 of 1.25 molar sulphuric acid?
Recommended: How to check NECO Result
NECO Chemistry Questions And Answers 2023 (Paper 2)
Don’t worry about this NECO Chemistry Questions And Answers 2023. All you need to do is to keep on refreshing this page for the 2023 NECO Chemistry Questions And Answers for this year. It will be posted here in few minutes.
Tips on How to Pass 2023 NECO Chemistry Examinations
The following guidelines will help you pass the 2023 NECO Chemistry examination with flying colours.
Have a Target and Work Towards Actualizing it
You have decided to pass NECO Chemistry 2023 and I am sure of that. Now, the next thing you should do is set targets.
You have told yourself, “I will score A in NECO Chemistry 2023”, that’s not all. You need to plan on how to make it happen. Create a timetable and master plan to achieve your goals.
Get the Recommended Textbook on Chemistry for 2023 NECO Examination
Normally, NECO recommends books for the examination. But apart from NECO Literature in English where certain novels are compulsory, you are free to use any good Chemistry textbook to prepare for NECO 2023 exam.
Some textbooks are more difficult to understand. If you have any topic you are finding difficult to understand, then get a textbook that will simplify the topics and make life better for you.
Do not Skip Chemistry Examples and Exercise you Will Come Across While Reading:
Many candidates are fond of skipping exercises and even examples while studying textbooks. In fact, we like notebooks so much that we could ask, “can I read my notebook and pass NECO Chemistry 2023?” Don’t be scared of attempting exercises in Biology. Face the challenges.
If you have any questions about the NECO Chemistry Questions and Answers 2023, kindly drop your question in the comment box.
Last Updated on April 4, 2023 by Admin
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