WAEC - Chemistry (2019)

  • 1
    The periodic table is an arrangement of elements according to their? 
    Respuesta
    (B)
    Atomic number
  • 2
    A solid with higher melting and boiling points is likely to be?
    Respuesta
    (C)
    An Electrovalent compound
  • 3
    Which of the following metals reacts slowly with cold water?
    Respuesta
    (C)
    Calcium
  • 4
    which of the following elements has the highest ionization energy?
    Respuesta
    (C)
    Flourine
  • 5
    The bleaching action of chlorine is through the process?
    Respuesta
    (D)
    Oxidation
  • 6

    If 6.5g of magnesium ribbon reacts completely with Hydrochloric acid, how many grams of hydrogen gas would be liberated?

    Mg(s) + 2 HCl(aq) --> MgCl 2(aq) + H 2(g)

    [ H = 1.0, Mg = 24.0 ]

    Respuesta
    (A)
    0.54g
  • 7
    Calcium and magnesium belong to the group of the periodic table because both?
    Respuesta
    (D)
    have same number of valence electrons
  • 8
    Which of the substances is non-polar?
    Respuesta
    (A)
    Bromine
  • 9

    Which of the following pairs of components have the same molecular mass?

    [ H = 1.0, C = 12.0, O = 16.0 ]

    Respuesta
    (C)
    Carbon (ii) Oxide and Ethene
  • 10
    When an equilibrium is established between dissolved and undissolved solutes, the solution is said to be?
    Respuesta
    (A)
    Saturated
  • 11

    How many moles of carbon(iv)oxide contains 16.0g of oxygen?

    [ C = 12.0, O = 16.0 ]

    Respuesta
    (D)
    0.50 mol
  • 12
    Stoichiometry is based on the law?
    Respuesta
    (D)
    conservation of mass
  • 13
    What is the percentage by mass of H in CH\(_3\)COOH ?
    Respuesta
    (C)
    6.7%
  • 14
    Which of the following compounds has coordinate bonds in its structure?
    Respuesta
    (A)
    Al\(_2\)Cl\(_6\)
  • 15
    The name of the compound CH\(_3\)C(CH\(_3\))\(_2\)CH\(_2\)CH\(_2\)CH\(_3\)
    Respuesta
    (D)
    2,2 - dimethyl pentane
  • 16
    The properties of a good primary standard solution include the following except?
    Respuesta
    (B)
    low molecular mass
  • 17

    What is the solubility of a salt X at 25ºC if the saturated solution of the salt contains 0.28g in 100cm\(^3\) of the solution in mol\dm\(^3\)? 

    [ X = 56.0g ]

    Respuesta
    (A)
    0.05
  • 18
    Vinegar is an aqueous solution of?
    Respuesta
    (C)
    ethanoic acid
  • 19
    which of the following solutions containing one mole per dm\(^3\) of the compound would have the lowest PH?
    Respuesta
    (B)
    hydrochloric acid
  • 20
    A sample of air was bubbled into water. The PH of the water slowly changed from 7 to 6. Which of the following gases in the samples caused the change?
    Respuesta
    (A)
    carbon(iv)oxide
  • 21
    The most suitable indicator for the reaction between NaOH and HCOOH is?
    Respuesta
    (D)
    phenolphthalein
  • 22
    consider the following reaction equation: 2Al(OH)\(_3\) + 3H\(_2\)SO\(_4\) Al\(_2\)(SO4)\(_3\)(aq)+6H\(_2\)O. How many moles of tetraoxosulphate(vi)acid is needed to produce 0.5mol of aluminium tetraoxosulphate(vi)?
    Respuesta
    (C)
    1.5
  • 23
    which of the following pairs of substances has the highest heat of neutralization?
    Respuesta
    (A)
    strong acid and strong base
  • 24
    When quicklime dissolves in water?
    Respuesta
    (B)
    heat is evolved
  • 25
    If the value of ΔH is positive for a reaction, it means that the reaction is?
    Respuesta
    (B)
    endothermic
  • 26
    Which of the following compounds is formed by the oxidation of ethanol?
    Respuesta
    (D)
    CH\(_3\)CO\(_2\)H
  • 27
    What is the characteristic of the gas liberated when dilute hydrochloric acid is added to Iron(ii)sulphide?
    Respuesta
    (D)
    turns lead(ii)ethanoate paper black
  • 28

    An organic compound contains 72% carbon, 12% hydrogen and 16% oxygen by mass. What is the empirical formula of the compound?

    [ H = 1.0. C = 12.0, O = 16.0 ]

    Respuesta
    (B)
    C\(_6\)H\(_{12}\)O
  • 29
    When excess chlorine is mixed with ethane at room temperature, the product formed is?
    Respuesta
    (A)
    1,2-dichloroethane
  • 30
    which of the following reagents could be used to distinguish between propan-1-ol and propan-2-ol
    Respuesta
    (A)
    H+ / K2Cr2O7
  • 31
    If a catalyst is added to a system, the temperature and the pressure remain constant, there would be no effect on the? 
    Respuesta
    (D)
    heat of reaction
  • 32

    consider the following reaction equation: 2NH\(_3 \) .+ 3Cl\(_2\) → N2 + 6HCl. 

    NH\(_3\) is acting as?

    Respuesta
    (A)
    a reducing agent
  • 33
    The oxidation of chromium in Cr\(_2\)O\(_7)\(-2\) ?
    Respuesta
    (C)
    +6
  • 34
    The process by which alkanoic acid reacts reversibly with alkanols is known as?
    Respuesta
    (B)
    esterification
  • 35
    If the oxidation potential of Mg and Al are +2.37 volts and + 1.66 volts respectively, then the Mg would?
    Respuesta
    (D)
    replace Al
  • 36

    consider the reaction represented by the following equation: 2SO\(_2\) + O\(_2\) ⇌ 2SO\(_3\) 

    A decrease in the pressure of the reaction would

    Respuesta
    (C)
    shift the equilibrium position to the left
  • 37
    In a mixture of gases which do not react chemically together, the pressure of the individual gas is?
    Respuesta
    (D)
    partial pressure
  • 38
    Biotechnology is applied in the? 
    Respuesta
    (A)
    treatment of sewage
  • 39
    which of the following organic compounds has the lowest boiling point?
    Respuesta
    (D)
    ( CH\(_3\) )\(_3\)
  • 40

    Consider the following reaction represented by the following equation:

    C\(_2\)H\(_2\) \(^{H_2}_{→}\) X \(^{H_2}_{→}\) Y. X and Y respectively are?

    Respuesta
    (B)
    ethene and ethane
  • 41
    Which of the following substances can be classified as heavy chemicals? 
    Respuesta
    (B)
    H\(_2\)SO\(_4\)
  • 42
    in Boyle's law?
    Respuesta
    (D)
    T is constant, V varies inversely with P
  • 43
    Which of the following apparatus is NOT used in volumetric analysis?
    Respuesta
    (C)
    Desiccator
  • 44
    One of the deductions from Rutherford's alpha particle scattering experiment is that?
    Respuesta
    (C)
    nuclei of atoms are positively charged
  • 45
    The atoms of \(^{64}_{29}\)Cu and \(^{65}_{30}\)Zn have the same number of?
    Respuesta
    (C)
    neutrons