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 1361:

  The shape of ammonia molecule is?

  Options:
  A) Trigonal planar
  B) Octahedral
  C) Square planar
  D) Tetrahedral
  Show Answer
  The correct answer is A .
• Question 1362: The compounds CH₃CH₂CHO and CH₃COCH₃ can be distinguished from each other using Options:
  A) Dilute ammonia
  B) Benedict's solution
  C) Tollen's reagent
  D) Sodium hydroxide solution
  Show Answer
  The correct answer is C .
• Question 1363:

  A basic postulate of the kinetic theory of gases is that the molecules of a gas move in straight lines between collisions. This implies that

  Options:
  A) collisions are perfectly elastic
  B) forces of repulsion exist
  C) forces of repulsion and attraction are in equilibrium
  D) collisions are inelastic
  Show Answer
  The correct answer is B .
• Question 1364:

  The electronic configuration of element Z is 1s${}^2$ 2s${}^2$ 2p${}^6$ 3s${}^2$ 3p${}^1$. What is the formula of the compound formed between Z and tetraoxosulphate (VI) ion.

  Options:
  A) Z${}_3$(SO${}_4$)${}_2$
  B) ZSO${}_4$
  C) Z${}_2$ SO${}_4$
  D) Z${}_2$(SO${}_4$)${}_3$
  Show Answer
  The correct answer is D .
• Question 1365: The combustion of ethene, C ₂H ₄, is given by the equation C ₂H ₄ + 30 ₂ → 2CO₂ + 2H₂ O; ∆H = - 1428 KJ. If the molar heats of formation of water and carbon (IV) oxide are - 286 kJ and - 396 kJ respectively, calculate the molar heat of formation of ethene in KJ Options:
  A) - 2792
  B) + 2792
  C) - 64
  D) + 64
  Show Answer
  The correct answer is D .
• Question 1366: When sodium nitrate dissolves in water, ∆H is positive. This means that? Options:
  A) the reaction is catalysed
  B) the reaction is complete
  C) the reaction is exothermic
  D) the reaction is endthermic
  E) sodium nitrate is highly soluble in water
  Show Answer
  The correct answer is D .
• Question 1367:

  N₂O_4(aq) $\rightleftharpoons$ 2NO_2(g) $△$H = +ve

  In the reaction above, an increase in temperature will

  Options:
  A) Increase the reactant production
  B) Increase the value of the equilibrium constant
  C) Shift the equilibrium to the left
  D) Decrease the value of the equilibrium constant
  Show Answer
  The correct answer is B .
• Question 1368:

  CO_(g) + H₂ O_(g) → CO_2(g) + H_2(g)

  Calculate the standard heat change of the reaction above, if the standard enthalpies of formation of CO_2(g), H₂O_(g) and CO_(g) and CO_(g) in KJ mol ^-1 are - 394 -242 and - 110 respectively.

  Options:
  A) + 262 KJ mol ^-1
  B) - 262 KJ mol ^-1
  C) + 42 KJ mol ^-1
  D) - 42 KJ mol ^-1
  Show Answer
  The correct answer is D .
• Question 1369:

  In the reaction:

  2Hl_(g) ↔ H_2(g) + l_2(g)' ΔH = 10 kj;

  The concentration of iodine in the equilibrium mixture can be increased by?

  Options:
  A) raising the pressure
  B) raising the temperature
  C) adding a catalyst
  D) lowering the pressure
  Show Answer
  The correct answer is B .
• Question 1370: What volume of 0.5 mol dm^-3 H₂SO₄ will exactly neutralize 20cm³ of 0.1 mol dm^-3 NaOH solution? Options:
  A) 2.0 cm³
  B) 5.0 cm³
  C) 6.8 cm³
  D) 8.3 cm³
  Show Answer
  The correct answer is A .