JAMB - Chemistry (1981)

• 1

  An element X has 127 neutrons and 82 electrons.
  Its atomic number is?

  回答

  (D)

  82
• 2

  When a bottle of Coca-Cola is opened, bubbles of evolve. The gas is?

  回答

  (C)

  carbon dioxide
• 3

  When glowing splint is inserted into the mouth of a jar containing a gas, the splint is extinguished. The gas gives a white precipitate when passing into barium hydroxide. The gas is?

  回答

  (E)

  carbondioxide
• 4

  An example of a strong electrolyte is?

  回答

  (D)

  sodium formate
• 5

  The oxidation number of manganese in KMnO₄ is?

  回答

  (D)

  +7
• 6

  Methane is member of the homologous series called?

  回答

  (D)

  alkanes
• 7

  For iron to rust, there should be present?

  回答

  (D)

  oxygen and moisture
• 8

  The mass number of an atom is?

  回答

  (E)

  the sum of numbers of proton and neutrons in the nucleus of the atom
• 9

  Sodium and potassium belong to the same group of the Periodic Table. This is because?

  回答

  (D)

  both have identical electronic configuration
• 10

  Oxidation is the process of?

  回答

  (B)

  loss of electrons
• 11

  the number of atoms in one mole of a substance is equal to?

  回答

  (B)

  the avogadro number
• 12

  Which of the following statements is NOT true of electrovalent compounds?

  回答

  (D)

  The elements forming the compounds normally have their valency electrons in a shared state
• 13

  If concentrated sulphric acid is added to sugar and warmed gently, the sugar changes from white to brown and finally to a black mas of carbon. In this reaction, concentrated sulphuric acid is acting as ?

  回答

  (C)

  a dehydrated agent
• 14

  In the reaction
  C + 2HNO₃ → CO₂ + NO₂ + NO + H₂O nitric acid is acting as?

  回答

  (C)

  an oxidizing agent
• 15

  The brown coloration in nitric acid prepared in the laboratory can be removed by?

  回答

  (B)

  bubbling air through the acid
• 16

  Which of the following processes takes place during electrolysis?

  回答

  (D)

  Negative ions are discharge at the anode by losing sufficient electrons to become neutral
• 17

  In the preparation of ammonia, which of the following is used as the drying agent?

  回答

  (A)

  CaO
• 18

  Which of the following can have an isomer?

  回答

  (B)

  C₄H₁₀
• 19

  Allotropes are elements having?

  回答

  (A)

  different physical but the same chemical properties
• 20

  A polymerization reaction is one in which?

  回答

  (A)

  small molecules form giant molecules
• 21

  Which of the following is the electronic configuration of sodium?
  (Atomic number of Na = 11)

  回答

  (C)

  1s² 2s²2p⁶ 3s¹
• 22

  In the reaction of oxygen with hydrogen to produce water, which of the following statements is true?

  回答

  (E)

  One molecule of oxygen reacts with two molecules of hydrogen to give two molecules of water
• 23

  Na₂CO₃ + 2HCI → 2NaCI + H₂O + CO₂. Using the above equation, what volume of carbondioxide, measured at s.t.p is liberated when 53g of sodium carbonate is dissolved in hydrochloric acid?
  (1 mole of gas occupies 22.4 dm³ at s.t.p)
  (Na = 23, C = 12, O = 16)

  回答

  (B)

  11.2 dm³
• 24

  When sodium nitrate dissolves in water, ∆H is positive. This means that?

  回答

  (D)

  the reaction is endthermic
• 25

  If an organic compound decolorizes bromine water then the compound is?

  回答

  (C)

  unsaturated
• 26

  When air is compressed?

  回答

  (D)

  its temperature increases
• 27

  Fats and oils are?

  回答

  (C)

  condensation products of long-chain fatty acids and glycerol
• 28

  Which of the following statements about phosphorus is NOT correct?

  回答

  (C)

  Phosphorus exists in two allotropic forms
• 29

  28.8 cm³ of nitrogen at 15°C is cooled to O°C at constant pressure, the new volume of nitrogen is?

  回答

  (C)

  27.3 cm³
• 30

  If 48,000 coulombs of electricity are required to discharge 0.5 mole of sodium from a molten sodium chloride mass, then the number of coulombs required to discharge 2 moles of lead from molten lead (ll) chloride is?

  回答

  (D)

  384,000
• 31

  The following compounds are given with their corresponding boiling points.
  Compound Boiling Point
  i.................................14°C
  ii................................24°C
  iii................................0°C
  iv................................120°C
  V.................................-2°C
  From the above information, indicate which of the following is correct?

  回答

  (D)

  Three of the compounds are gaseous at 20 °C
• 32

  The products of the reaction between dilute sulphuric acid and sodium thiosulphate crystals are?

  回答

  (C)

  Na₂SO₄ + SO₂ + S + H₂O
• 33

  Which of the following is NOT a true statement of the kinetic Theory of Gases?

  回答

  (D)

  Every molecule has the same kinetic energy at a particular temperature
• 34

  The electronic configuration of elements X and Y are X = 2, 8, 6; Y = 2, 8, 7. The bond in the compound formed by X and Y is expected to be?

  回答

  (B)

  covalent
• 35

  5cm³ of a saturated solution of sodium chloride at 30°C gave, on careful evaporation, 1.95g of solid salt. The solubility of sodium chloride at 30°C?
  
  (Na = 23, Cl = 35.5)

  回答

  (D)

  6.67 mole dm³
• 36

  In the extraction of iron, which of the following reactions does NOT take place in the blast furnace?

  回答

  (B)

  2Fe₂O₃ + 3C → 4Fe + 3CO₂
• 37

  Pure sulfuric acid is a liquid of 1.84 density. What volume of it would be required to prepare 250 cm3 of 2.0 M solution?
  
  
  
  (H = 1, S = 32, O = 16)

  回答

  (B)

  2.66
• 38

  What mass of sodium carbonate solution is in 500 cm³ of 0.1 molar sodium carbonate solution?
  
  (Na = 23, C = 12, O = 16)

  回答

  (B)

  5.3 g
• 39

  Which of the following compounds and elements would sublime on exposure to the atmosphere?

  回答

  (D)

  Iodine
• 40

  When hydrogen sulphide and sulphur dioxide are each passed in turn into a solution of potassium dichromate?

  回答

  (E)

  only hydrogen sulphide deposits sulphur
• 41

  Which one of the following metals is not normally extracted by chemical reduction because of its position in the electrochemical series?

  回答

  (D)

  Potassium
• 42

  If one mole of aluminium contains 6 x 10²³ atoms of aluminium, how many atoms are contained in 0.9g of aluminium?
  (Al = 27)

  回答

  (C)

  2.0 x 10²²
• 43

  4g each of aluminium foil and aluminium powder were introduced respectively into flasks P and Q.
  Flask P was treated with warm bench sodium hydroxide and all the aluminium dissolved in one hour. Flask Q was treated with cold sodium hydroxide and all the aluminium dissolved in 10 minutes. What was responsible for Q reacting faster than P?

  回答

  (E)

  Q has a greater surface area for the reaction than P
• 44

  What happens when the nitrates of potassium, calcium, zinc and copper are separately heated?

  回答

  (E)

  The nitrates of calcium, zinc and copper decompose to their oxides
• 45

  The scale formation in a kinetic used for boiling water is caused by the presence in water of?

  回答

  (C)

  calcium hydrogen carbonate