Chemistry Exam Past Questions and Answers | JAMB, WAEC and NECO

Chemistry is the study of the substances that make up matter. It looks at their properties, how they react with each other, and how these reactions can create new substances.

• Question 991: Phosphorus burns in oxygen according to the equation P₄ + 50₂ → P₄O₁₀. How many litres of oxygen will be required at S.T.P for complete oxidation of 12.4g of phosphorus? [P = 31,O = 16 and molar volume of a gas at S.T.P = 22.4 litres] Options:
  A) 5. 20
  B) 11. 20
  C) 2. 24
  D) 20. 20
  E) 6. 20
  Show Answer
  The correct answer is B .
• Question 992: Which of the following molecules is held together by hydrogen bond? Options:
  A) CH₄
  B) HBr
  C) H₂SO₄
  D) HF
  Show Answer
  The correct answer is D .
• Question 993: A student prepares 0.5 M solution each of hydrochloric and ethanoic acids and then measured pH. The result would show that the? Options:
  A) pH values are equal
  B) HCI solution has a higher pH
  C) sum of the values is 14
  D) ethanoic acid solution has a higher pH
  Show Answer
  The correct answer is D .
• Question 994:

  When water drops are added to calcium carbide in a container and the gas produced is passed through a jet and lighted, the resultant flame is called an?

  Options:
  A) Oxyethene
  B) Oxyhydrocarbon flame
  C) Oxyacetylene flame
  D) Oxymethane flame
  Show Answer
  The correct answer is C .
• Question 995:

  For the reaction NH₄NO₂ $\to$ N₂ + 2H₂O, calculate the volume of nitrogen that would be produced at S. T. P from 320 g of the dioxonitrate(iii)salt. (Relative atomic masses: N = 14, O = 16, H = 1)

  Options:
  A) 2.24 dm ³
  B) 224 dm³
  C) 1.12 dm ³
  D) 112 dm ³
  E) 4.48 dm ³
  Show Answer
  The correct answer is D .
• Question 996: An example of a secondary amine is? Options:
  A) propylene
  B) di-butylamine
  C) methylamine
  D) trimethylamine
  Show Answer
  The correct answer is B .
• Question 997: Which of the following gases can be collected by the upward displacement of air? Options:
  A) NO
  B) H ₂
  C) NH₃
  D) Cl ₂
  Show Answer
  The correct answer is D .
• Question 998:

  

  Use the above graph above to answer this question . CH₃-C = CH $\frac{Na}{liqN{H}_3}$> P, Compound P, in the above reaction, is

  Options:
  A) A
  B) B
  C) C
  D) D
  Show Answer
  The correct answer is B .
• Question 999:

  2X_(aq) + MnO_2(s) + 4H⁺_(aq) → X_2(g) + Mn²⁺_(aq) + 2H₂O.

  The reaction above can be used for the laboratory preparation of all halogens except fluorine because it is?

  Options:
  A) a poisionous gas
  B) an oxidizing agent
  C) electronegative in nature
  D) highly reactive
  Show Answer
  The correct answer is D .
• Question 1000: When a pressure cooker is half filled with water, and heated to boiling point, then the pressure inside the cooker will? Options:
  A) decrease, since only a fraction of the water molecules has changed to vapour
  B) remain constant, because the total number of water molecules has not changed
  C) increase, because the water molecules can now reach every part of the sealed tube
  D) decrease, since water boils under reduced pressure
  E) increase, because the water vapour molecules now strike the walls of the tube more frequently because of their increased velocity
  Show Answer
  The correct answer is E .