WAEC - Chemistry (1988)

  • 1
    Equilibrium is said to be attained in reversible reaction when
    Cevap
    (D)
    the rates of the forward and backward reactions are equal
  • 2
    An acid present in proteins is
    Cevap
    (B)
    amino acid
  • 3
    The following are uses of sulphur except
    Cevap
    (E)
    coating of steel to prevent rusting
  • 4
    The reaction represented by the equation NaOH(aq) + HCI(aq) → NaCI(aq) + H2O(/)
    Cevap
    (B)
    is a neutralization
  • 5
    Which of the following compound is aromatic?
    Cevap
    (A)
    Benzene
  • 6
    Which of the following does not affect the rate of a chemical reaction?
    Cevap
    (C)
    The enthalpy change for the reaction
  • 7
    Which of the following does not affect the rate of a chemical reaction?
    Cevap
    (C)
    The enthalpy change for the reaction
  • 8
    Given that 32.0g sulphur contains 6.02 x 10 23 sulphur atoms how many atoms are there in 2.70g of aluminium? {Al = 27, S =32}
    Cevap
    (C)
    6.02 x 1022
  • 9
    The empirical formula of hydrocarbon containing 0. 12 mole of carbon and 0.36 mole of hydrogen is
    Cevap
    (B)
    CH3
  • 10
    A salt which loses mass when exposed to air is
    Cevap
    (C)
    efflorescent
  • 11
    Detergents are better than soaps for laundry because
    Cevap
    (C)
    scum is precipitated when soaps are used with hard water but not with stergents
  • 12
    Which of the following is used as an anaesthetic?
    Cevap
    (B)
    CHCI3
  • 13
    Which of the following types of hybridization gives rise to tetrahedral molecules?
    Cevap
    (C)
    sp3
  • 14
    Which of the following is a neutral oxide?
    Cevap
    (E)
    Nitrogen oxide
  • 15
    Which of the following statements is not correct?
    Cevap
    (C)
    Chlorine exhibits allotopy
  • 16
    The following are uses of radioactive isotopes except for
    Cevap
    (E)
    determining equilibrum positions
  • 17
    The main characteristic feature of transition metals is that they
    Cevap
    (D)
    have variable oxidation states
  • 18
    The following are heavy chemicals except
    Cevap
    (E)
    dyes
  • 19
    What quantity of silver is deposited when 96500C of electricity is passed through a solution containing silver ions? (Ag = 108, 1F = 96500C)
    Cevap
    (E)
    108g
  • 20
    Bubbling of carbon (IV)oxide into calcium hydroxide solution results in the formation of
    Cevap
    (A)
    CaCO3
  • 21
    Which of the following is not decomposed by heat?
    Cevap
    (D)
    Na2CO3
  • 22
    Which of the following is not true of the rusting of iron?
    Cevap
    (A)
    Rusting is a reduction process
  • 23
    Which of the following is not true of the rusting of iron?
    Cevap
    (A)
    Rusting is a reduction process
  • 24
    What volume of oxygen will be left unreacted when a mixture of 100cm3 of hydrogen and 200cm,sup>3,/sup> of oxygen are exploded in a eudiometer?
    Cevap
    (C)
    150cm3
  • 25
    How many isomers can be obtained from C4H10?
    Cevap
    (C)
    2
  • 26
    Water gas is a mixture of?
    Cevap
    (E)
    CO and H2
  • 27
    Which of the following metals cannot extracted from its ore by using carbon (ll) oxide as the reducing agent?
    Cevap
    (C)
    Al
  • 28
    Which of the following is not a naturally occurring iron ore?
    Cevap
    (A)
    FeCl2
  • 29
    Which of the following equations represents the reaction of chlorine with hot concentrated sodium hydroxide solution?
    Cevap
    (C)
    6NaOH + 3CI2 → NaCIO3 + 5NaCI + 3H2O
  • 30
    Aqueous sodium trioxocarbonate (IV) solution is alkaline because
    Cevap
    (E)
    sodium triocarbonate (IV) is hydrolysed in water
  • 31
    Which of the following correctly explains why iodine crystals change directly into the gaseous state when heated?
    Cevap
    (C)
    lodine molecules are held together by weak forces
  • 32
    Which of the following is a waste product in the Solvary Process for the manufacture of sodium trioxocarbonate (IV)?
    Cevap
    (E)
    Calcium chloride
  • 33
    When copper (ll) chloride solution is treated with excess aqueous ammonia, a deep blue solution results This is due to the presence of
    Cevap
    (E)
    [cU(NH3)4] ions
  • 34
    The complex salt formed when aluminium dissolves in sodium hydroxide solution is
    Cevap
    (E)
    NaAI(OH)4
  • 35
    The reaction represented by the equation C(s) + H2O(l) → CO(s) + H 2(s) was carried out at 27oC if the enthalpy change was + 4500 J and the entropy change was + 12J, what was the free energy change? (∆G = ∆H - T∆S)
    Cevap
    (D)
    + 900 J