WAEC - Chemistry (2023)

  • 1
    The vapour density of an organic compound with the molecular formula \(C_2H_4O_2\), is
    [H=1.0, C=12.0, O= 16.0]
    Përgjigju
    (D)
    30
  • 2
    The following statements are correct except
    Përgjigju
    (C)
    there is large decrease in the volume of a solid metal when pressure is applied to it.
  • 3
    Which of the following reactions represents the hydrolysis of an alkanoate?
    Përgjigju
    (D)
    \(CH_3COOCH_2CH_3 + H_2O ⇌H^+⇌ CH_3COOH + CH_3CH_2OH\)
  • 4
    The following steps are scientific methods except
    Përgjigju
    (D)
    Open-mindedness
  • 5
    Alkenes can be manufactured by
    Përgjigju
    (B)
    the cracking of hydrocarbons.
  • 6
    The formation of a bond between hydrogen and a highly electronegative atom results in
    Përgjigju
    (A)
    polarity
  • 7

    Which of the elements in the table below would react more readily with chlorine?
     

    Element

    Ionization energy (KJ \(mol^{-1} \times 10^{-3}\))

    W 12.0
    X 21.0
    Y 106.0
    Z 200.0

     

    Përgjigju
    (C)
    W and X only
  • 8
    Which of the following properties does not give evidence of the kinetic theory of matter?
    Përgjigju
    (C)
    Polymerization
  • 9
    Dilute trioxonitrate (V) acid does not produce hydrogen when it reacts with metals because
    Përgjigju
    (D)
    it is a strong oxidizing agent.
  • 10
    Which of the following statements is correct?
    Përgjigju
    (D)
    An alkane with 49 carbon atoms contains 100 hydrogen atoms
  • 11
    A mixture containing two salts of different solubility can be separated by
    Përgjigju
    (B)
    crystallization.
  • 12
    Species that occur in a reaction pathway but not in the overall reaction are known as
    Përgjigju
    (D)
    Intermediates
  • 13
    How many moles are there in 3.0 g of \(O_2\)? [O = 16.0]
    Përgjigju
    (B)
    0.0930 moles.
  • 14
    Which of the following equimolar solutions has the highest conductivity?
    Përgjigju
    (A)
    \(H_2SO{_4(aq)}\)
  • 15
    The pair of compounds that belongs to the same homologous series is
    Përgjigju
    (A)
    \(C_2H_6\) and \(C_4H_{10}\)
  • 16
    Which of the following equations does not illustrate correctly one of the reactions of chlorine?
    Përgjigju
    (B)
    \(Cl_2 + 2NaF → 2NaCl + F_2\)
  • 17
    The salt solution formed firm a reaction between ethanoic acid and sodium hydroxide solution would be
    Përgjigju
    (C)
    basic
  • 18
    The separation technique that is suitable for separating iodine from tetrachloromethane is
    Përgjigju
    (A)
    solvent extraction
  • 19
    Consider the following reaction equation:
    \(2SO_3(g) → 2SO_2(g) + O_2\)(g)
    ∆H = +198 kJ/mol
    Which of the following statements about the reaction is correct?
    Përgjigju
    (D)
    198 kJ of energy is absorbed
  • 20
    Arrange the following compounds in decreasing order of their boiling points: \(NH_3\), HF, \(SiH_4\), \(CH_4\)
    Përgjigju
    (A)
    HF,\(NH_3\), \(SiH_4\), \(CH_4\)
  • 21
    Copper (II) ions are able to participate in co-ordinate covalent bonding because they
    Përgjigju
    (C)
    have vacant d-orbital
  • 22
    What takes place at the cathode during electrolysis?
    Përgjigju
    (D)
    Cations are discharged.
  • 23
    Carbon is deposited in the exhaust pipes of cars because of
    Përgjigju
    (B)
    incomplete combustion of petrol
  • 24
    Which of the following laws or theory cannot be explained by the application of the kinetic theory of gases?
    Përgjigju
    (A)
    Dalton's atomic theory
  • 25
    How many unpaired electrons are present in \(_{26}Fe^{3+}\)?
    Përgjigju
    (D)
    5
  • 26
    A consequence of global warming is
    Përgjigju
    (C)
    flooding
  • 27
    Going down group II in the periodic table normally
    Përgjigju
    (B)
    melting point increases
  • 28
    The primary component of natural gas
    Përgjigju
    (B)
    methane
  • 29
    The gas that is less dense than air is
    Përgjigju
    (A)
    nitrogen
  • 30
    The periodic property that is used to determine whether a covalent molecule is polar or not is
    Përgjigju
    (D)
    electronegativity
  • 31
    If \(100^3\) of a saturated solution of sodium tetraoxosulphate (VI) at 30° C contains 10.5 g of the salt, what would be its solubility at this temperature? [(\(Na_2SO_4\) = 142]
    Përgjigju
    (B)
    0.74 mol dm-3
  • 32
    A compound that could be dried by using conc. tetraoxosulphate (VI) acid and not by calcium oxide is likely to be
    Përgjigju
    (D)
    an acid anhydride
  • 33
    Which of the statements about gases is not correct?
    Përgjigju
    (D)
    Gases are highly soluble in water at high temperatures
  • 34
    Determine the volume of 0.100 mol of HCl in \(0.250 mol dm^3\) of solution.
    Përgjigju
    (D)
    \(400cm^3\)
  • 35
    Positive ions in a sea of electrons are found in
    Përgjigju
    (B)
    metallic bonds
  • 36
    An element X has two isotopes, \(^{65}X_{30}\) and \(^{66}X_{30}\) with relative abundance of 60 % and 40% respectively. The relative atomic mass of X is
    Përgjigju
    (D)
    65.40
  • 37
    Which of the following statements about the collision theory is correct?
    Përgjigju
    (C)
    The rate of reaction is proportional to the number of effective collisions
  • 38
    Which of the following elements has its valence electrons in the s-orbital?
    Përgjigju
    (C)
    Sodium
  • 39
    Petrochemistry is an example of
    Përgjigju
    (A)
    applied chemistry
  • 40
    The molecule that has a non-polar covalent bond is
    Përgjigju
    (C)
    \(Cl_2\)
  • 41
    The reduction half equation of the following reaction is:
    \(Zn_{(s)} + CuSO_{4(aq)} → ZnSO_{4(aq)} + Cu_{(s)}\)
    Përgjigju
    (C)
    \(Cu^{2+}_{(aq)} + 2e^- → Cu_{(s)}\)
  • 42
    Why are \(H_2SO_4\) and \(CaCl_2\), not suitable for drying ammonia gas? They
    Përgjigju
    (D)
    react with the gas
  • 43
    Isoelectronic species have the same number of
    Përgjigju
    (B)
    electrons
  • 44
    Which of the following gases has the lowest rate of diffusion?
    [H=1.0, C=12.0, N = 14.0, O= 16.0]
    Përgjigju
    (D)
    Oxygen
  • 45
    An example of a crystalline substance that does not possess water of crystallization is
    Përgjigju
    (B)
    sodium tetraoxosulphate (VI).