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Friday, 14 August 2026
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Chemistry Past Questions and Answers

Topic: Simple calculations

Jamb Chemistry Questions - Simple calculations

Question 1:
How many grams of HBr would exactly be required to react with 2 g of propyne? (C =12, H=1, Br = 80)
  • A 4. 1 g
  • B 6. 1 g
  • C 8. 1g
  • D 16.2g
View Answer & Explanation
Question 2:
In the preparation of some pure crystals of Cu (NO3)2 starting with CuO, a student gave the following statements as steps he employed. Which of these shows a flaw in his report ?
  • A Some CuO was reacted with excess dilute H<sub style='font-size: smaller;'>2</sub>SO<sub style='font-size: smaller;'>4</sub>
  • B The solution was concentrated
  • C When the concentrate was cooled, crystals formed were removed by filtration
  • D The crystals were washed with very little cold water
  • E The crystals were then allowed to dry
View Answer & Explanation
Question 3:
How many grams of H2SO4 are necessary for the preparation of 0.175 dm3 of M 6.00 M H2SO4?
(S = 32.06, O = 16.00 H = 1.00)
  • A 206.0 g
  • B 103.0 g
  • C 98.1 g
  • D 51.5 g
View Answer & Explanation
Question 4:
The set-up above would be useful for determining the amount of
  • A Oxygen in air
  • B Water vapour in air
  • C CO<sub style='font-size: smaller;'>2</sub> in air
  • D Arygen in air
View Answer & Explanation
Question 5:
The diagram above is the solubility curve of a solute, X. Find the amount of X deposited when 500cm3 of a solution of X is cooled from 60oC to 20oC.
  • A 0.750 mole
  • B 0.950 mole
  • C 2.375 moles
  • D 4.750 moles
View Answer & Explanation