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 1951: Water is said to be 'hard' if it Options:
  A) easily forms ice
  B) has to be warmed before sodium chloride dissolves in it
  C) froms an insoluble scum with soap
  D) contains nitrates
  E) contains sodium ions
  Show Answer
  The correct answer is C .
• Question 1952:

  The number of molecules of Carbon(iv)Oxide produced when 10.0g of CaCO${}_3$ is treated with 0.2dm${}^3$ of 1 Mole of HCL in the equation

  CaCO${}_3$ + 2HCL $\to$ CaCl${}_2$  + H${}_2$ O + CO${}_2$  , is ?

  Options:
  A) 1.00 X 10${}^{23}$
  B) 6.02 X 10${}^{23}$
  C) 6.02 X 10${}^{22}$
  D) 6.02 X 10${}^{24}$
  Show Answer
  The correct answer is C .
• Question 1953: NH_3(g) + HCl_(s) → NH ₄Cl _(s)The entropy change in the system above is Options:
  A) positive
  B) zero
  C) negative
  D) intermediate
  Show Answer
  The correct answer is C .
• Question 1954: A given quantity of a gas occupies a volume of 228 cm³ at a pressure of 750mm Hg. What will be its volume at atmospheric pressure? Options:
  A) 220 cm³
  B) 225 cm³
  C) 230 cm³
  D) 235 cm³
  Show Answer
  The correct answer is B .
• Question 1955: In the reaction E+F ↔ G+H, the backward reaction is favoured if the concentration of Options:
  A) F is increased
  B) E is increased
  C) E is reduced
  D) G is reduced
  Show Answer
  The correct answer is C .
• Question 1956: Water can be identified by the use of? Options:
  A) anhydrous copper (II) tetraoxosulphate (VI)
  B) anhydrous sodium trioxocarbonate (IV)
  C) potassium heptaoxochromate (VII)
  D) copper (II) trioxocaronate (IV)
  Show Answer
  The correct answer is A .
• Question 1957: 0.07g of a hydride of carbon occupies 56.0cm³ at S.T.P. when vaporized and contains 14.29% by mass of hydrocarbon is(C = 12, H = 1) Options:
  A) CH₄
  B) C₂H₂
  C) C₂H₄
  D) C₂H₆
  E) C₃H₈
  Show Answer
  The correct answer is C .
• Question 1958: The pH of a solution obtained by mixing 100cm³ of a 0.2M solution of NaOH is? Options:
  A) 1.3
  B) 7.0
  C) 9.7
  D) 12.7
  Show Answer
  The correct answer is D .
• Question 1959: A molar solution of caustic soda is prepared by dissolving Options:
  A) 40 g NaOH in 100 g of water
  B) 40 g NaOH in 1000 g of water
  C) 20 g NaOH in 500 of solution
  D) 20 g NaOH in 1000 g of solution
  E) 2o g NaOH in 80 g of solution
  Show Answer
  The correct answer is B .
• Question 1960:

  GAS	CO${}_2$	N${}_2$	O${}_2$
  % BY VOLUME	4	72	24

  The above table shows the compositions of the atmosphere of planet X. Which of these gases are present inhigherpercentages on earth?

  Options:
  A) CO${}_2$ and O${}_2$
  B) N${}_2$ and CO${}_2$
  C) CO${}_2$, O${}_2$ and N${}_2$
  D) O${}_2$ and N${}_2$
  Show Answer
  The correct answer is D .