JAMB - Chemistry (1990)

• 1

  Which of the following is a physical change?

  回答

  (C)

  The dissolution of sodium chloride in water
• 2

  In a reaction: \(SnO_{2} + 2C → Sn + 2CO\) the mass of coke containing 80% carbon required to reduce 0.302 kg of pure tin oxide is?
  (Sn - 119, O - 16, C - 12).

  回答

  (C)

  0.06 kg
• 3

  Cr₂O₇ + 6Fe²⁺ + 14H⁺ → 2Cr³⁺ +6Fe³⁺ + 7H₂O. In the above , the oxidation number of chromium changed from?

  回答

  (A)

  +7 to +3
• 4

  In the reaction 1O^-₃ + 5l^- + 6H⁺ → 31₂ + 3H₂O, the oxidizing agent is?

  回答

  (C)

  1O^-
• 5

  Fe\(_2\)O\(_{3(s)}\) + 2Al\(_{(s)}\) → Al\(_2\)O\(_3\) + 2Fe\(_{(s)}\). If the heats of formation of Al\(_2\)O\(_3\) and Fe\(_2\)O\(_3\) are - 1670 kJmol\(^{-1}\) and - 822 kJmol\(^{-1}\) respectively, the enthalpy change in kJ for the reaction is ?

  回答

  (C)

  -848
• 6

  Iron galvanized with zinc is cathodically protected from corrosion. This is because?

  回答

  (A)

  zinc has a more positive oxidation potential than iron
• 7

  Which of the following samples will react fastest with dilute trioxonitrate (V) acid?

  回答

  (D)

  5 g of powered CaCO₃ AT 50°C
• 8

  In the reaction:
  2Hl_(g) ↔ H_2(g) + l_2(g)' ΔH = 10 kj;
  
  The concentration of iodine in the equilibrium mixture can be increased by?

  回答

  (B)

  raising the temperature
• 9

  Which of the following gases can be collected by the upward displacement of air?

  回答

  (D)

  Cl ₂
• 10

  The brown fumes given off when trioxonitrate (V) acid is heated consist of ?

  回答

  (A)

  NO₂ and O₂
• 11

  Which of the following tests will completely identify anyone of surphur (VI) oxide, hydrogen, carbon (IV) oxide and nitrogen (II) oxide?

  回答

  (B)

  Pass each gas into lime water
• 12

  In the Haber process for the manufacture of ammonia, the catalyst commonly used is finely divided ?

  回答

  (C)

  iron
• 13

  A metallic oxide which reacts with both HCl and NaOH to give salt and water only can be classified as?

  回答

  (D)

  an amphoteric oxide
• 14

  Which of the following metals will liberate hydrogen from steam or dilute acid?

  回答

  (B)

  Iron
• 15

  Coal fire should not be used in poorly ventilated rooms because ?

  回答

  (C)

  of the acumulation of CO which causes suffocation
• 16

  The major component of the slag from the production of iron is?

  回答

  (D)

  calcium trioxosilicate (IV)
• 17

  Sodium hydroxide should be stored in properly closed containers because it?

  回答

  (A)

  readily asborbs water vapour to air
• 18

  To make coloured glasses, small quantities of oxides of metals which form coloured silicates are often added to the reaction mixture consisting of Na₂CO₃ and SiO₂. Such a metals is a?.

  回答

  (D)

  copper
• 19

  Which of the following compounds gives a yellow residue when heated and also reacts with aqueous sodium hydroxide to give a white gelatinous precipitate soluble in excess sodium hydroxide solution?

  回答

  (B)

  ZnCO₃
• 20

  A cycloalkane with the molecular formula C₅H₁₀ has ?

  回答

  (C)

  three isomers
• 21

  The label on a reagent bottle containing a clear organic liquid dropped off.The liquid was neutral to litmus and gave a colourless gas with metallic sodium. The liquid must be an?

  回答

  (C)

  alkanol
• 22

  Alkaonic acids have low volatility compared with alkanols because they?

  回答

  (D)

  form two hydrogen bonds while alkanols form one
• 23

  The octane number of a fuel whose performance is the same as that of a mixture of 55 g of 2,2,4- trimethly pentane and 45 g of n-heptane is ?

  回答

  (B)

  55
• 24

  Which of the following is formed when maltose reacts with concentrated tetraoxosulphate (VI) acid ?

  回答

  (C)

  Charcoal
• 25

  If a gas occupies a container of volume 146 cm3 at 18°C and 0.971 atm, its volume in cm3 at s.t.p is?

  回答

  (A)

  133
• 26

  The volume occupies by 1.58g of a gas at s.t.p is 500cm³. What is the relative molecular mass of the gas?
  
  (G.M.V at s.t.p = 22.40dm³)

  回答

  (D)

  71
• 27

  Equal volumes of CO,SO2, NO2 and H2S were released into a room at the same point and time. Which of the following gives the order of diffusion of the gases to the opposite corner of the room?
  (S = 32, C = 12, O = 16, N = 14, H = 1)

  回答

  (D)

  CO,H₂S,NO₂,SO₂
• 28

  A basic postulate of the kinetic theory of gases is that the molecules of a gas move in straight lines between collisions. This implies that?

  回答

  (A)

  collisions are perfectly elastic
• 29

  .....................P....Q.....R......S
  Proton..............13....16....17.....19
  Electron............13....16....17.....19
  Neutron.............14....16....35.....20
  
  Which of the four atoms P,q,R and in S in the above data can be described by the following properties relative atomic mass is greater than 30 but less than 40; it has an odd atomic number and forms a unipositive ion in solution?

  回答

  (D)

  S
• 30

  Which of the following terms indicates the number of bonds that can be formed by an atom?

  回答

  (B)

  Valence
• 31

  X(g) → X\(^-\)(g). The type of energy involved in the above transformation is?

  回答

  (D)

  electron affinity
• 32

  Chlorine, consisting of two isotopes of mass numbers 35 and 37, has an atomic mass of 35.5.
  The relative abundance of the isotope of mass number 37 is?

  回答

  (B)

  25
• 33

  10.0 dm³ of air containing H₂S as an impurity was passed through a solution of Pb(NO₃)₂ until all the H₂S had reacted. The precipitate of PbS was found to weigh 5.02 g. According to the equation:
  
  Pb(NO₃)₂ + H₂S → PbS + 2HNO₃ the percentage by volume of hydrogen sulphide in the air is?
  
  
  
  (Pb = 207, S = 32, GMV at s.t.p = 22.4dm³)

  回答

  (C)

  4.70
• 34

  A blue solid, T, which weighed 5.0g was placed on a table. After 8 hours, the resulting pink solid was found to weigh 5.5g. It can be inferred that substance T?

  回答

  (B)

  is hygroscopic
• 35

  The solubility in moles per dm³ of 20g of CuSO₄ dissolve in 100 of water at 180°C is?
  
  (Cu = 63.5, S = 32, O = 16)

  回答

  (C)

  1.25
• 36

  Smoke consist of?

  回答

  (B)

  solid or liquid particles dispersed in gas
• 37

  Na₂C₂O₄ + CaCl₂ → CaC₂O₄ + 2NaCl. Given a solution of 1.9g of sodium oxalate in 50g of water at room temperature, calculate the minimum volume of 0.1 M calcium oxalate using the above equation?

  回答

  (A)

  1.40 χ 10² dm³
• 38

  2.0g of a monobasic acid was made up to 250 cm³ with distilled water. 25.00 cm³ of this solution required 20.00cm³ of 0.1 M NaOH solution for complete neutralization. The molar mass of the acid is?

  回答

  (C)

  100 g
• 39

  What is the concentration of H⁺ ions in moles per dm³ of a sodium of pH 4.398?

  回答

  (A)

  4.0 χ 10^-5
• 40

  What volume of 11.0 M hydrochloric acid must be dilute to obtain 1 dm3 of 0.05 M acid?

  回答

  (A)

  0.05 dm³
• 41

  If 10.8 g of silver is deposited in a silver coulometer volume of oxygen liberated is?

  回答

  (A)

  0.56 dm³
• 42

  0.1 faraday of electricity deposited 2.95 g of nickel during electrolysis of an aqueous solution.
  Calculate the number of moles of nickel that will be deposited by 0.4 faraday?
  
  (Ni = 58.7)

  回答

  (A)

  0.20
• 43

  

  Changes in the physical in the scheme above.The letter X,Y and Z respectively represent

  回答

  (A)

  sublimation, condensation and freezing
• 44

  

  Use the graph above to answer this question. The structure of cis-2-butene is

  回答

  (B)

  B
• 45

  

  What is the IUPAC name for the hydrocarbon?

  回答

  (C)

  2,4-dimethylhex 3-ene