JAMB CBT Software 2025 - Free Download
JAMB CBT 2025 - Candidates, Schools, Centres, Resellers - Get Ready!

Chemistry WAEC Past Questions

Clear Selections
Change Subject Post a Question Check Syllabus Study My Bookmarks Past Questions Videos Watch Video Lessons Download App

JAMB CBT Mobile App 2025 - Free Download
JAMB CBT 2025 - Candidates, Schools, Centres, Resellers - Get Ready!
JAMB CBT Software 2025 - Free Download
WAEC Past Questions, Objective & Theory, Study 100% offline, Download app now - 127076
1931

a. Starting with calcium chloride, describe briefly how a solid sample of calcium trioxocarbonate (IV) can be prepared in the laboratory.

b. With relevant equations outline the procedure for the purification of impure copper.

c. Copper reacts with concentrated trioxonitrate (V) acid:  i. write a balanced chemical equation for the reaction;

ii. state what would be observed in the reaction,

iii. state why the copper is oxidized;

iv. an excess of copper is added to 25.0 \(cm^3\) of 16.0 mol \(dm^3\) \(HNO_3\). Calculate the volume of the gas formed at s.t.p. [H=1.0, N=14.0, O= 16.0, Cu=63.0; Molar volume of gas at .s.t.p.=22.4 \(dm^3\)]

di. Pure \(HNO_3\), is a colourless liquid but when exposed to air, it turns yellowish-brown in colour. Explain briefly this observation.

ii. Write a balanced equation for the laboratory preparation of hydrogen trioxonitrate (V) acid.

View Answer & Discuss WAEC 2023
1932

a. Describe how iron and aluminum reacts with each of the following substances: i.  dilute \(H_2SO_4\); ii.   dilute \(HNO_3\)

bi. Write an equation for the burning of sulphur in air.

ii. Name the catalyst used in the contact process.

iii. In the contact process, why is an excess of air used?

iv. Why is it necessary to cool the catalyst used in 5(b)(ii)?

v. Give a reason why the air used in the contact process needs to be as clean as possible.

vi. State two reasons why SO2 should not be discharged into the atmosphere.

ci. State the reagents and conditions used in the laboratory preparation of chlorine.

ii. State two uses of chlorine.

di. Name the drying agents for each of the following gases: 1. Hydrogen; 

i2.  sulphur (IV) oxide; 

i3. Ammonia.

ii1. State the components of the following
      Bronze;  ii2. Brass.


 

View Answer & Discuss WAEC 2023
1933

Which of the following gases could be collected by downward displacement of air?

  • A. Chlorine
  • B. Hydrogen
  • C. hydrogen chloride
  • D. Sulphur(IV) oxide
View Answer & Discuss (7) WAEC 2024
JAMB CBT 2025 - Candidates, Schools, Centres, Resellers - Get Ready!
JAMB CBT Software 2025 - Free Download
JAMB CBT Mobile App 2025 - Free Download
WAEC Past Questions, Objective & Theory, Study 100% offline, Download app now - 127076
1934

Which of the following substances has the lowest boiling point?

  • A. Aqueous sodium chloride
  • B. Ethanol
  • C. Tetrachloromethane
  • D. Water
View Answer & Discuss (1) WAEC 2024
1935

The branch of science that deals with the nature and properties of substances and how one substance can be converted to another is known as 

  • A. biology
  • B. chemistry
  • C. geography
  • D. physics
View Answer & Discuss WAEC 2024
Start a Free Practice Test
 
JAMB CBT 2025 - Candidates, Schools, Centres, Resellers - Get Ready!
JAMB CBT Software 2025 - Free Download
WAEC Past Questions, Objective & Theory, Study 100% offline, Download app now - 127076
JAMB CBT Mobile App 2025 - Free Download