JAMB - Chemistry (1983)

• 1

  X is a crystalline salt of sodium solution of X in water turns litmus red and produces a gas which turns lime water milky when added to sodium carbonate. With barium chloride solution, X gives hydrochloric acid. X is

  回答

  (C)

  NaHSO ₄
• 2

  The alkanol obtained from the production of soap is

  回答

  (B)

  glycerol
• 3

  The flame used by welders in cutting metals is

  回答

  (D)

  oxy-acetylene flame
• 4

  Consecutive members of an alkane homologous serires differ by

  回答

  (B)

  CH₂
• 5

  If an element has the electronic configuration 1s ² 2s² 2p³ 3s² 3p⁴, it is

  回答

  (D)

  a p-Block element
• 6

  Some copper (ll) sulphate pentahydrate (CuSO₄ 5H₂O), was heated at 120 ^oC with the following results. Wt of crucible = 10.00 g; Wt of crucible + CuSO₄ 5H₂O =14.98g; Wt of crucible + residue = 13.54 g. How many molecules of water of crystalization were lost?
  
  [H = 1, Cu = 63.5, O = 16, S = 32]

  回答

  (D)

  4
• 7

  The three-dimensional shape of methane is

  回答

  (D)

  tetrahedral
• 8

  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

  回答

  (D)

  an ester
• 9

  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.
  
  The molecular formula of X is

  回答

  (B)

  C₆H₁₂O₆
• 10

  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.
  
  Reaction of X with yeast forms the basis of the

  回答

  (C)

  brewing industry
• 11

  A mixture of common salt, ammonium chloride and barium sulphate can best be separated by

  回答

  (C)

  sublimation followed by addition of water then filtration
• 12

  Which of the following relationships between the pressure P, the volume V and the temperature T, represents an ideal gas behaviour?

  回答

  (B)

  P \(\alpha\) T/V
• 13

  The colour imparted to a flame by calcuium ion is

  回答

  (C)

  brick-red
• 14

  In the reaction M + N P;∆H = + QKJ. Which of the following would increase the concentration of the product?

  回答

  (E)

  Increasing the temperature
• 15

  In which of the following processes is iron being oxidized?
  
  1 Fe + H₂SO₄ → FeSO₄ +H₂
  
  2 FeSO₄ + H₂S → FeS + H₂SO₄
  
  3 2FeCI₂ + Cl₂ → 2FeCl₃
  
  4 2FeCl₃ + SnCl₂ + → 2FeCl₂ + SnCl₄

  回答

  (D)

  1 and 3
• 16

  In the reaction Fe + Cu²⁺ \(\to\) Fe²⁺ + Cu,iron displaces copper ions to from copper. This is due to the fact that

  回答

  (E)

  iron is higher in the electrochemical series than copper
• 17

  

  The correct name of the compound with the above structural formula is

  回答

  (A)

  2-methylbut -1-ene
• 18

  How many isomeric forms are there for the molecular formula C₃H₆Br₂?

  回答

  (D)

  4
• 19

  A piece of burning sulphur will continue to burn in a gas jar of oxygen to give misty fumes which readily dissolved in water. The resulting liquid is

  回答

  (C)

  trioxosulphate (IV) acid
• 20

  Sodium sulphate decahydrate (Na₂SO₄.10 H₂O) on exposure to air loses all its water of crystallization.
  The process of loss is known as

  回答

  (A)

  efflorescence
• 21

  Which of the following happens during the electrolysis of molten sodium chloride?

  回答

  (E)

  Chloride ion is oxidized
• 22

  Crude petroleum pollutant usually seen on some Nigerian creeks and waterways can be dispersed or removed by

  回答

  (C)

  pouring organic solvents to dissolve the petroleum
• 23

  An element is electronegative if

  回答

  (D)

  it has a tendency to gain electrons
• 24

  Solutions X, Y, and Z have PH values 3.0. 5. 0 and 9. 0 respectively. Which of the following statements is correct?

  回答

  (E)

  Z is the least acidic
• 25

  In the reactions
  
  (I) H₂ (g) + 1/2O₂(g) → H₂O(l); ∆H = -286 KJ
  
  (II) C(s) + O₂g) → CO₂ (g); ∆H = -406 KJ the equations imply that

  回答

  (C)

  less heat is evolved in (l)
• 26

  Which of these metals, Mg, Fe, Pb and Cu will dissolve in dilute HCI?

  回答

  (D)

  Mg and Fe only
• 27

  Stainless steel is an alloy of

  回答

  (B)

  carbon, iron and chromium
• 28

  Which volume of 0.5 M H ₂SO₄ will exactly neutralize 20 cm ³ of 0.1 M NaOH solution?

  回答

  (A)

  2.0 cm ³
• 29

  Which of the following pair of gases will NOT react further with oxygen at a temperature between 30^oC AND 400^oC

  回答

  (C)

  NO₂ and SO₃
• 30

  Some metals are extracted from their ores after some preliminary treatments by electrolysis (L), some by thermal decomposition(T), some by a combination of both processes (TL). Which set-up in the following for the extraction of iron, copper, and aluminium is correct?

  回答

  (E)

  lron (T) copper (L), aluminium (TL)
• 31

  In the preparation of some pure crystals of Cu (NO₃)₂ starting with CuO, a student gave the following statements as steps he employed. Which of these shows a flaw in his report ?

  回答

  (A)

  some CuO was reacted with excess dilute H₂SO₄
• 32

  Which of the following separation processes is most likely to yield high quality ethanol (>95%) from palm wine?

  回答

  (C)

  fractional distillation with a dehydrant
• 33

  Increasing the pressure of a gas

  回答

  (D)

  increases the density of the gas
• 34

  2.5 g of a hydrate barium salt gave on heating, 2.13 g of the anhydrous salt. Given that the relative molecular mass of the of the anhydrous salt is 208, the number of molecules of water of crystallization of the barium salt is

  回答

  (D)

  2
• 35

  3. 06 g of a sample of potassium trioxochlorate (V) (KCIO\(_3\)) was required to make a saturated solution with 10cm\(^3\) of water at 25°C. The solubility of the salt at 25°C is [K =39, Cl = 35.5, O = 16]

  回答

  (C)

  2.5 moles dm³
• 36

  The cracking process is very important in the petroleum industry because it.

  回答

  (C)

  yields more engine fuels
• 37

  A gas that can behave as a reducing agent towards chlorine and as an oxidizing agent toward hydrogen sulphide is

  回答

  (C)

  SO₂
• 38

  Which of the following solutions will give a white precipitate with barium chloride solution and a green flame test?

  回答

  (B)

  CuSO₄
• 39

  The mass of an atom is determined by

  回答

  (D)

  the number of neutrons and protons
• 40

  Which of the following is a neutralization reaction?

  回答

  (E)

  Addition of trioxonitrate (V) acid (nitric acid) to potassium hydroxide solution
• 41

  A jet plane carrying 3,000 kg of ethane burns off all the gas forming water and carbondioxide. if all the carbondioxide is expelled and all the water formed is condensed and kept on board the plane, then the gain in weight is

  回答

  (D)

  2, 400 kg
• 42

  Liquid X, reacts with sodium trioxocarbonate (IV) (Na₂CO₃) to give a gas which turns calcium chloride solution milky X is

  回答

  (D)

  an acid
• 43

  Which of the following statements is FALSE?

  回答

  (B)

  Sodium metal dissolves in water giving oxygen
• 44

  When sodium dioxonitrate (lll) (NaNO₂) dissolves in water, ∆H is positive. The process of dissolution is

  回答

  (B)

  endothermic
• 45

  The equilibrium reaction between copper (l) chloride and chlorine at 25^oC and 1 atmosphere is represented by the equation:
  2CuCl +Cl₂ ⇌ 2 CuCl₂ ∆H = - 166 KJ. Which of the following statements is TRUE for the reaction, pressure remaining constant?

  回答

  (B)

  more CuCl₂ is formed at 10^oC