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 1371: 300 cm³ of gas has a pressure of 800 mmHg. If the pressure is reduced to 650 mmHg, find its volume Options:
  A) 243.75 cm³
  B) 369.23 cm³
  C) 738.46 cm³
  D) 1733.36 cm³
  Show Answer
  The correct answer is B .
• Question 1372: In the reaction 1O^-₃ + 5l^- + 6H⁺ → 31₂ + 3H₂O, the oxidizing agent is? Options:
  A) H⁺
  B) l^-
  C) 1O^-
  D) l₂
  Show Answer
  The correct answer is C .
• Question 1373:

  Which one of the following is not a mixture?

  Options:
  A) Air
  B) Mercury
  C) Milk
  D) Cement
  Show Answer
  The correct answer is B .
• Question 1374: The polymer used in making car rear lights is Options:
  A) perspex
  B) bakeelite
  C) polystyrene
  D) polyacrylonitrile
  Show Answer
  The correct answer is A .
• Question 1375: 30cm³ of oxygen at 10 atmospheres pressure is placed in a 20 dm³ container. Calculate the new pressure if temperature is kept constant? Options:
  A) 6.7 atm
  B) 15.0 atm
  C) 60.0 atm
  D) 66. 0 atm
  Show Answer
  The correct answer is B .
• Question 1376: In a flame test for calcium, the flame appears Options:
  A) green when viewed through a blue glass
  B) blue when viewed through a blue glass
  C) orange -red when viewed through a blue glass
  D) brick-red when viewed through a blue-glass
  Show Answer
  The correct answer is D .
• Question 1377: When 50cm³ of a saturated solution of sugar (molar mass 342.0g) at 40^oC was evaporated to dryness, 34.2g of dry solid was obtained. The solubility of sugar at 40^oC is Options:
  A) 10.0 moles dm^-3
  B) 7.0 moles dm^-3
  C) 3.5 moles dm^-3
  D) 2.0 moles dm^-3
  Show Answer
  The correct answer is D .
• Question 1378:

  What is the PH of 0.00 1 moldm${}^3$ solution of the sodium hydroxide

  Options:
  A) 14
  B) 13
  C) 12
  D) 11
  Show Answer
  The correct answer is D .
• Question 1379:

  An organic compound with a vapour density 56.5 has the following percentage composition:C =53.1% N = 12.4%, O = 28.3%, H = 6.2%. The molecular formula of the compound is

  Relative atomic masses: N = 14, O = 16, C = 12, H = 1 )

  Options:
  A) C₃H₆O₂N
  B) C₅H₆O₂N
  C) (C₅H₇O₂N)_1/2
  D) C₅H₇O₂N
  E) (C₅H₇O₂N)₂
  Show Answer
  The correct answer is D .
• Question 1380: Solutions X, Y, and Z have PH values 3.0. 5. 0 and 9. 0 respectively. Which of the following statements is correct? Options:
  A) All the solutions are acidic
  B) All the solutions are basic
  C) Y and Z are more acidic than water
  D) Y is more acidic than X
  E) Z is the least acidic
  Show Answer
  The correct answer is E .