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 1781: Sulphur Options:
  A) forms two alkaline oxides
  B) is spontaneously flammable
  C) burns with a blue flame
  D) conducts electricity in the molten state
  E) is usually stored in the form of sicks in water
  Show Answer
  The correct answer is C .
• Question 1782: The noble gas, argon,is used for Options:
  A) electric arc welding
  B) welding brass
  C) underwater welding
  D) steel welding
  Show Answer
  The correct answer is A .
• Question 1783: In which order are the following salts sensitive to light? Options:
  A) Agl > AgCl > AgBr
  B) AgCl > Agl > AgBr
  C) AgBr > AgCl > Agl
  D) AgCl > AgBr > Agl
  Show Answer
  The correct answer is D .
• Question 1784:

  The ratio of the initial to the final pressure of a given mass of gas is 1:1.5. Calculate the final volume of the gas if the initial volume was 300cm${}^3$ at the same temperature.

  Options:
  A) 120cm${}^3$
  B) 200cm${}^3$
  C) 450cm${}^3$
  D) 750cm${}^3$
  Show Answer
  The correct answer is B .
• Question 1785:

  The general formula of alkanones is

  Options:
  A) RCHO
  B) R${}_2$CO
  C) RCOOH
  D) RCOOR
  Show Answer
  The correct answer is B .
• Question 1786:

  

  In the graph above, the activation energy of the catalyzed reaction is

  Options:
  A) 100KJ
  B) 300KJ
  C) 250KJ
  D) 200KJ
  Show Answer
  The correct answer is A .
• Question 1787: The removal of rust from iron by treatment with tetraoxosulphate (IV) acid is based on the? Options:
  A) hydrolysis of the iron
  B) reaction of acid with base
  C) oxidationof the rust
  D) dehydration of the iron
  Show Answer
  The correct answer is D .
• Question 1788: Which of the following ions require the largest quantity of electricity for discharge at an electrode? Options:
  A) 2.0 mole of Q ³⁺
  B) 2.5 mole of R²⁺
  C) 4.0 mole of Y^-
  D) 3.0 mole of T^-
  Show Answer
  The correct answer is A .
• Question 1789: The ion that can be used as an oxidizing agent is Options:
  A) Au³⁺
  B) Fe³⁺
  C) F^-
  D) Ca²⁺
  Show Answer
  The correct answer is C .
• Question 1790:

  

  The following graph demonstrates the rate of reaction between calcium carbonate (marble)and dilute hydrochloric acid. The graph shows that the rate of reaction is initially greatest when

  Options:
  A) the initial slope of the curve is steepest and this occur when small pieces of marble are used and is due to a small surface area of reactant
  B) the occur when large pieces of marble are used and is due to a small surface area of reactant
  C) the initial slope of the curve is steepest and this occurs when small pieces of marble are used and is due to a large surface area of reactant
  D) the initial slope of the curve is steepest and this occur when large surface area of reactant
  E) the initial slope of the curve is least steep and this occur when small pieces of marble are used and is due to the increased surface area of the reactant
  Show Answer
  The correct answer is C .