30 Most Likely Repeated Questions In JAMB Chemistry 2023

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Likely Questions In JAMB Chemistry For 2023

Note: The questions below are frequently asked questions in JAMB chemistry and is posted here strictly for practice.

1. What is the shape of a molecule of CCl4?

A. Pyramid

B. tetrahedral

C. Trigonal planar

D. linear

ANSWER: B (Tetrahedral)

2. A sample of gas with an initial volume of 2.5 dm3 is heated and then allowed to expand to 7.5 dm3 at constant at pressure. What is the ratio of the final temperature of the initial absolute temperature?

A. 3:1

B. 1:3

C. 2:5

D. 5:2

ANSWER: A (3:1)

3. 6g of Mg was to 100cm3 of 1 moldm3 H2 SO4 . What mass of Mg remained undissolved? (Mg = 24)

A. 0.24g

B. 2.4g

C. 3.6g

D. 0.36g

ANSWER: C (3.6)

4. Which of the following will act as both oxidizing agents and reducing agents?

A. H2 S

B. NH3

C. Cl2

D. SO2

ANSWER: D ( SO2 )

5. A metal which can be used as sacrificial anode for preventing corrosion of length of iron pipe is

A. copper

B. magnesium

C. silver

D. lead

ANSWER: C (Silver)

6. Which of the following increases as boiling water changes to steam?

A. Temperature of the system

B. degree of disorder of the system

C. number of molecule

D. Activation energy

ANSWER: B (Degree of disorder of the system)

7. Which of the following is stable to heat

A. NaHCO3

B. ( NH4 )2 SO4

C. Ag NH3

D. K2 CO3

ANSWER: D ( K2 CO3 )

8. Which of the following will precipitate in dil. HCl

A. ZnS

B. Na2 S

C. Fe S

D. CuS

ANSWER: D ( CuS )

9. Which of the following does NOT contain aluminum as a component?

A. Over-head cables

B. Duralumin

C. Container for caustic soda

D. Container for trioxonitrate (v) acid

ANSWER: C (Container for caustic soda)

10. The removal of rust from iron by treatment with tetraoxosulphate (vi) acid is based on the

A. Hydrolysis of the iron

B. Reaction of acid with base

C. Oxidation of the rust

D. Dehydration of the iron

ANSWER: D ( Dehydration of the iron )

11. Which of the following constitutes a mixture? I. Petroleum II. Rubber latex III. Vulcanizer’s solution IV. Carbon (iv) sulphide

A. I, II and III

B. I, II and IV

C. I and II only

D. I and IV

ANSWER: A ( I, II and III)

12. 30 cm3 of oxygen at 10 atmosphere pressure is placed in a 20 dm3 container. Calculate the new pressure if the temperature is kept constant.

A. 6.7 atm

B. 15.0 atm

C. 6.0 atm

D. 66.0 atm

ANSWER: A ( 15.0 atm)

13. A sample of gas exerts a pressure of 8.2 atm when confined in a 2.93 dm3 container at 20c. The number of moles of gas in the sample is

A. 1. 00

B. 2.00

C. 3.00

D. 4.00

ANSWER: A ( 1.00)

14. A quantity of air passed through a weighted amount of alkaline pyrogallol. An increase in the weight of the pyrogallol would result from the absorption of

A. nitrogen

B. neon

C. argon

D. oxygen

ANSWER: D ( Oxygen)

15. There is a large temperature interval between the melting point and the boiling point of metal because:

A. metals have a very high melting point

B. metals conduct heat very rapidly

C. melting does not break the metallic bond but boiling does

D. the crystal lattice of metal is easily broken

ANSWER: A ( metals have very high melting point)

16. Copper (II) tetraoxosulphate (IV) is widely used as

A. fertilizer

B. fungicide

C. Disinfectant

D. purifier

ANSWER: B ( fungicide)

17. Which of the following substances is not a homogeneous mixture?

A. filtered sea water

B. soft drinks

C. flood water

D. writing ink

ANSWER: C ( floodwater)

18. Ethene, when passed into concentrated H2SO4, is rapidly absorbed. The product is diluted with water and then warmed to produce

A. Ethanol

B. diethyl ether

C. ethanal

D. diethyl sulphate

ANSWER: A ( Ethanol)

19. A certain liquid has a high boiling point. It is viscous, non-toxic, and miscible with water to be hygroscopic; this liquid most likely to be

A. CH3CH2CH2CH2OH

B. CH3CH2CHOH3

C. CH3CH2CH2CH2OH3

D. CH3OHCHOH2OH

ANSWER: D (CH3OHCHOH2OH)

20. Which of the following statement is TRUE of the complete hydrolysis of a glyceride by sodium hydroxide?

A. 3 moles of NaOH are required for each mole of glyceride

B. 3 moles of glycerol are produced

C. only one mole of soap is formed

D. concentrated H2SO4 is essential for the completion of the reaction.

ANSWER: A (3 moles of NaOH are required for each mole of glyceride)

21. A piece of radioactive element has initially 8.0×10^22 atoms. The half life of two days after 16 days the number of atom is

A. 5×10^21

B. 5×10^22

C. 25×10^21

D. 25×10^22

ANSWER: B (5×10^21)

22. Chlorine is a common bleaching agent. This is not true with

A. wet litmus paper

B. printers ink

C. wet pawpaw leaf

D. most wet fabric dyes

ANSWER: B (printers ink)

23. Calcium forms complexes with ammonia because

A. it is a transition metal

B. it is an s-block element

C. it has empty d-orbital

D. it forms colourless compounds

ANSWER: C (it has empty d-orbital)

24. The IUPAC name for CICH2-CH2-CH2-OH is

A. 1-chloropropan-3-ol

B. 3-chloropropan-1-ol

C. 1 cholorpropano

D. 3-chloropropanol

ANSWER: B (3-choropropan-1-ol)

25. An organic compound decolourized acidified KMnO4 solution but failed to react with ammonical AgNO3 solution. The organic compound is likely?

A. a carboxylic acid

B. Alkane

C. Alkene

D. Alkyne

ANSWER: D (Alkyne)

26. A certain volume of gas at 298k is heated such that its volume and pressure are now four times the original values. What is the new temperature?

A. 18.6K

B. 100.0K

C. 298.0K

D. 4768.0K

ANSWER: D (4768.0K)

27. The boiling point of water, ethanol, toulene and butan-2-ol are 373.0k, 351.3k, 383.6k and 372.5k respectively, which liquid has the highest vapour pressure at 323.0k

A. water

B. toluene

C. ethanol

D. butan-2-ol

ANSWER: C (ethanol)

28. The function of sulphur during the vulcanization of rubber is to

A. act as a catalyst for the polymerization of rubber molecules

B. convert rubber from thermosetting to thermoplastic polymer

C. form chains which bind rubber molecules together

D. break down rubber polymer molecules

ANSWER: C (form chains which bind molecules together)

29. Complete dehydrogenation of ethyne yields

A. benzene

B. methane

C. ethane

D. propane

ANSWER: D (propane)

30. Mixing aqueos solution of barium hydroxide and sodium tetraoxocarbonate (iv) yields a white precipitate of

A. Barium oxide

B. Sodium tetraoxocarbonate

C. Sodium hydroxide

D. Barium tetraoxocarbonate

ANSWER: D (Barium tetraoxocarbonate)

FAQs : 

What Are The Tricks to answer JAMB Chemistry Questions

Knowing some constants like mass and the atomic number of elements in chemistry, Avogadro’s number, the mass of the proton, neutron and electron, speed of light e.t.c will help you to answer some bonus questions asked by Jamb without giving some constants.

It is also important to note some popular principles and laws in chemistry as most of them would form part of the question you will see in your Jamb Chemistry questions.

Due to no time or lack of it, let’s quickly move to 2022/2023 JAMB Chemistry questions and answers. Use them to prepare for mock and JAMB examination.