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 701:

  What technique is suitable for separating a binary solution of potassium chloride and potassium trioxochlorate (V)?

  Options:
  A) Fractional crystallization
  B) Fractional distillation
  C) Filtration
  D) Evaporation
  Show Answer
  The correct answer is A .
• Question 702:

  3Cu + pHNO₃ →3Cu(NO)₂ + 4H₂ O + xNO

  In the equation above, the values of p and x respectively are

  Options:
  A) 1 and 3
  B) 2 and 3
  C) 6 and 2
  D) 8 and 2
  Show Answer
  The correct answer is D .
• Question 703:

  Which of the following metals is the most essential in the regulation of blood volume, blood pressure and osmotic equilibrium?

  Options:
  A) Zinc
  B) Manganese
  C) Sodium
  D) Iron
  Show Answer
  The correct answer is C .
• Question 704: The difference between colloides and and suspensions is brought out clearly by the fact that while colloids? Options:
  A) do not scatter light, suspensions do
  B) can be separated by filtration, suspension cannot be so separated
  C) can be separated by a membrane, suspensions cannot
  D) do not settle out on standing, suspensions do
  Show Answer
  The correct answer is D .
• Question 705:

  The atomic weight of nitrogen is?

  Options:
  A) 10
  B) 12
  C) 14
  D) 16
  Show Answer
  The correct answer is C .
• Question 706: A gas exerts pressure on its container because Options:
  A) some of its molecules are moving faster than others
  B) of the collision of the molecules with each other
  C) of the mass of the molecules of gas
  D) the molecules of a gas colide with the walls of the container
  Show Answer
  The correct answer is D .
• Question 707:

  An unknown organic compound X has a relative molecular mass of 180. It is a colourless crystaline solid, readily soluble in water. X contains the elements C, H and O in the atomic ratio 1: 2:1. The compound has a sweet teste and melts on heating. In the presence of yeast and in the absence of air, X is converted to compound Y and a colourless gas. Compound Y reacts with sodium metal to produce a gas Z which gives a 'pop' sound with a glowing splint. Y also reacts with ethanoic acid to give a sweet smelling compound W.

  Compound W is

  Options:
  A) a soap
  B) an oil
  C) an alkane
  D) an ester
  E) sucrose
  Show Answer
  The correct answer is D .
• Question 708:

  

  In the diagram above, X is the

  Options:
  A) Enthalphy
  B) Activated complex
  C) Activation energy
  D) Enthalphy change
  Show Answer
  The correct answer is D .
• Question 709:

  

  Copper sulphate solution was electrolysed using the apparatus show above. Which of the following changes are observed?

  Options:
  A) The bulb lights and copper is deposited at both electrodes
  B) the bulb lights and copper is deposited at the anode and disappears from the cathode
  C) the bulb lights and copper is deposited at the cathode and oxygen liberated at the anode
  D) the bulb lights and copper is deposited at the cathode and disappears from the anode
  E) the bulb lights but no additional changes are observed
  Show Answer
  The correct answer is D .
• Question 710:

  RS_(aq) + HF_(aq) → RF_(s) + HS_(aq)

  ΔH = -65.7 kj mol^(-1).

  From the equation above, it can be deduced that

  Options:
  A) the heat content of the reactants is lower than that of the products
  B) the heat content of the reactants is higher than that of the products
  C) the reaction is slow
  D) a large amount of heat is absorbed
  Show Answer
  The correct answer is B .